Download Free Pass4sure 922-098 exam practice exam 922-098 practice exam comprises of 922-098 free pdf in PDF record configuration and VCE test system in Installable programming. Both of the 922-098 exam questions and Practice Test are completely refreshed before it opens up in your download area. Set aside your time and cash, simply register and download.

Exam Code: 922-098 Practice test 2023 by team
Communication Server 1000 Rls.5.0 Troubleshooting
Nortel Troubleshooting book
Killexams : Nortel Troubleshooting book - BingNews Search results Killexams : Nortel Troubleshooting book - BingNews Killexams : Guide to color troubleshooting

Coloring plastics at the press is one of the most functional, value-added features a molder can impart to a molded product. Self-coloring not only improves aesthetic properties, it can also Improve UV stability and make processing easier. Also, adding color at the machine is almost always less expensive than purchasing precolored material from a supplier.

There's just one catch. Once the color system has been incorporated into the polymer matrix, it becomes an integral part of the material and may alter its engineering properties as well as its processability. As a result, it's important to be aware of some of the common problems involved with melt-coloring plastics and how to avoid them.

Generally, aesthetic flaws can be attributed to three different causes: equipment (machine, mold, ancillary equipment), molding (process), and design (part and tool)/formulation (base resin and colorant). In some instances, the flaw may be the result of problems in more than one category, but generally, there is always a predominant issue. Similarly, some problems may have more than one symptom, so several different "problems" may be showing up in parts that have the same root cause, which calls for the same corrective action.

When troubleshooting aesthetic problems in molded parts, it's important to begin with an open mind. Since successful molding is an interdependent combination of machinery, labor, material, and design, troubleshooting is often more complicated than people initially expect.

Identifying the Problem
The first step in determining if the flaw is caused by a molding- or colorant-related problem is to inspect parts visually to determine what the problem looks like. Some flaws are very distinctive and quickly lead you to their root cause. Others are less distinct and may be caused by a number of factors that fall into several categories. Consequently, some basic troubleshooting and root-cause/corrective-action work is required. The table with this article provides a list of common aesthetic flaws that could involve colorant and their most probable causes.

The next step is to find out when and where the flaws are being reported. Flaws that show up immediately upon molding require one approach to troubleshooting-for instance, processing and equipment issues are easier to check at this point. In this case, the troubleshooting process might start by asking the following questions:

  • Have the process settings changed?
  • How frequently does the problem occur?
  • Is the proper equipment in place and functioning?
  • Was the colorant properly metered in and mixed with the melt?
  • Is the colorant compatible with the base resin?

However, field failures that occur after months or even years will suggest a different starting point-a focus that begins with either part design or formulation:

  • Is UV exposure higher than initially predicted?
  • Is the part being used as originally designed?
  • Has the part been inadvertently exposed to some chemical agent?
  • Is the aesthetic change a symptom of a larger problem (for example, loss of mechanical properties)?

Regardless of the simplicity or complexity of a molding project, good documentation practices should be in effect and followed diligently by all team members. Processing parameters should be noted throughout. Not only will this practice help molders stabilize their process and create good parts faster, it will also provide a baseline for reference should the process drift and problems arise.

Common Sense- Often Uncommon
The best way to begin troubleshooting an aesthetic problem in which colorant and/or special-effects packages are involved is to rule out the colorant package as the source of the problem. This is done by running uncolored (natural) material through on the same process settings to see if the problem recurs. If it does reappear, then it's likely that the problem is not caused by the colorant package, although the base resin could still be part of the problem. If the problem disappears, then the colorant package is the proper place to begin your investigation. It's important to remember that aesthetic issues may exist that are difficult to see without color. In other words, a colored background will frequently magnify aesthetic problems.

While it is outside the scope of this article to cover the entire process, one thing that should be mentioned is that proper troubleshooting requires a sensible, methodical approach. Unless a Taguchi design of experiments study is being conducted, only one parameter at a time should be changed, and its effect should be carefully evaluated and documented. Then the parameter should be returned to its baseline setting before another parameter is changed.

While the following guidelines involve colorant-related problems, we will also touch briefly on processing, equipment, and design issues, indicating areas of concern that can affect colorant and/or aesthetics. If the troubleshooting process indicates that one of these categories is a likely cause, then there are a number of good resources, both human and written, that can and should be consulted for further help.

Troubleshooting Guidelines

As with any manufacturing process, molding a quality product consistently requires proper equipment, design, material, and processing procedures. The following list of considerations are provided as general guides when beginning to troubleshoot aesthetic problems.

1. First, check the following four equipment areas.

Screws/nonreturn valves. In most cases, a general-purpose screw will work well with colorants, depending on the letdown ratio, chromaticity, and base resin used. Although it's usually not necessary, a growing number of injection molders are using mixing screws to aid in color distribution. Processes with high throughput, short cycle times, and large shot sizes or those that use difficult-to-color resins will often benefit from this type of screw.

As with screws, selection of non-return valves is often resin-specific. Ball check valves are more shear intensive and can aid in color distribution, although this method can prove problematic when processing parameters such as screw speed, backpressure, and barrel temperatures are pushed close to the base resin's limits, leading to both colorant and resin degradation.

Screw and barrel wear. A worn screw or barrel-regardless of the design-will inhibit mixing, causing a loss in plasticating quality and therefore color distribution.

Barrel capacity. As a general rule, using more than 60 percent of the barrel capacity with a GP screw is considered to be pushing the processing envelope for good color incorporation. Of course, this is cycle-time dependent. The barrel's L/D ratio is also important. For example, shorter barrels (18:1) are less conducive to a good mix, while longer barrels (24:1) provide a longer mix environment, but also longer residence time. It's important to keep an eye on material residence time, because excessive residence can degrade either the base resin or the colorant, or both, while insufficient time in the barrel may lead to distribution issues.

Colorant handling and dispensing. One of the keys to successful color processing is an accurate blending/distribution of colorant and base resin before both enter the molding machine. When blending equipment is used, production personnel must be aware of proper operation, calibration, and maintenance. If the equipment is not properly calibrated to the process, any money saved by coloring the raw materials will be lost in wasted product.

For solid (salt and pepper mix) colorants, there are many different options, such as drum tumblers or auger mixers. For blending concentrates and powders at the machine, either volumetric or gravimetric feeders are used. Volumetric feeders are both less expensive and potentially less accurate than gravimetric types because they feed colorant based on speed vs. time. Gravimetric feeders weigh and blend each component in the mix. For liquid colorant, special volumetric pumps are typically used to handle the color accurately and neatly. (See the sidebar on p. 87 for definitions of common colorant-system formats and their functions.)

2. Tooling design can also impact aesthetics.

Gates and runner systems. Proper gating and runner types should be considered at the design table. It's important to remember that additional heat generated by a hot manifold or pin gate during injection fill can affect the integrity of the color. If it's known ahead of time that such tooling is being used, a colorant provider can formulate the color package differently.

Knitlines. Anticipating aesthetic issues during the early design stage is very important, especially if knitlines are a factor. When moldfilling analysis or experience indicates knitlines are likely, color formulation changes can be made with certain resin families that will Improve the appearance of knitlines. Of course, this issue is more easily resolved during the early stages of part and tooling design.

Mold texture. Also an important consideration during the design stages is mold texture, since it can affect how the eye perceives color. The presence of gloss and/or texture in the tool can make what would otherwise be an exact color match appear very different. Gloss should be considered in relation to both the mold and resin being processed, since some materials naturally have higher gloss.

3. Take a good look at part design.

Color/special effects. It's important to understand that a joint blessing and challenge of molding color and/or special effects is that the color package may accentuate design or molding problems that are already present in a part, such as knitlines, slight sinks, or stress-whitening marks near the base of a snapfit. Taking color back out and running the part in natural resin may appear to make the problem disappear, but in reality the problem, if it is a molding or design issue, is probably still there, and just not as visible.

The problem will be accentuated in chromatic colors and high-gloss designs. So if it's something that can otherwise be lived with, slight design modifications may solve the problem. On the other hand, certain problems, like stress-whitening marks, can often be hidden by the correct use of color or possible reformulation.

When integrally colored, molded parts of dissimilar materials are mated with other molded or painted parts, they must often match in color, gloss, and texture. Here, it's important to work closely with the resin and color suppliers to ensure that the parts will match as closely as possible when they are new and that they will fade at the same rate throughout the lifetime of the assembly.

Bosses/ribs/knitlines/parting lines. Wherever there is a flow interruption in the part design-from bosses, ribs, or even converging flow fronts on multiple gated parts-there is a strong possibility of sink marks, knitlines, and compromised mechanical integrity because knitlines are always weaker than the surrounding resin. Since the orientation of the material in these areas shifts, the refractive index across this region of the part will also shift, posing aesthetic challenges for many special-effects packages. Therefore, these interruptions should be designed into nonvisible faces and noncritical areas of the part.

4. Take these processing tips to heart.

Screw speed. For color processing, a slower screw speed is usually better to avoid shearing and burning the colorant and to ensure proper color distribution, cycle time permitting.

Backpressure. Higher backpressure promotes more thorough mixing, especially with a GP screw, again, if cycle time permits. A maximum value of 300 psi (2 MPa) is generally recommended by machinery OEMs.

Resin temperature. Higher melt temperatures also promote better mixing, as long as the processor is careful not to begin melting too early in the feed section of the screw, although this too can be resin dependent.

5. Be aware of these colorant and formulation issues.

Resin and colorant compatibility. The melt index relationship between the base resin and color are very important and should be considered early in the design. Additionally, certain pigments react with particular resins to a greater or lesser degree.

For instance, some organic pigments tend to dissolve and disappear (or change color) in styrenic polymers. Similarly, many dyes tend to change color or disappear in nylon polymers, which are weak reducing agents that effectively destroy the chromophore component of the dye that provides color. Additionally, except in special cases, dyes are not recommended for use in olefins because of very limited solubility and a potential for color migration (crocking). Further, dyes can act as a plasticizer in some materials, reducing thermal properties or even reacting with the resin itself to produce various effects.

Phthalocyanine (phthalo) pigments can be problematic, since they can act as nucleators, causing often uncontrollable shrinkage and warpage problems in crystalline resins. Fluorescent dyes also can pose problems in certain environments. They lack thermal stability for use in many engineering resins, they chemically react with nylon, and they lack UV stability for use in most outdoor applications.

A final category of problems is often found with polymer blends and alloys. There can be phase boundaries between the various components of these materials that can cause light scattering and a resulting milkiness. Hence, obtaining chromatic colors can become a costly undertaking due to the large amount of colorant that needs to be introduced to counteract the milkiness-often at the expense of economic concerns and critical physical or mechanical properties.

Carrier specification. The specific carrier for the color and its flow properties vs. the base resin play an important role in color distribution, and must be considered during the initial design. The carrier should melt in the late-feed or early-transition sections of the screw to ensure proper distribution of the pigment or dye in the mix. If the carrier has either too high or too low a melting point, the colorant will not be properly distributed in the melt, and finally in the molded part.

Other additives. Special additives for the colorant package can help with some color-related problems. However, these ingredients are normally not incorporated until processing efforts have failed, primarily because they add cost that may make the end product less cost-effective.

Grade can make a difference. It's important to remember that not all resin families or even grades within the same family are interchangeable with a given color package, let alone with different pigment or dye packages in the same chemical family. Further, since most colorant suppliers custom formulate their packages to a specific resin grade by a particular manufacturer, if the resin provider is switched after the color package has been formulated, it should be retested.

A good example of this is the fairly wide fluctuation that can be seen in the natural color of polypropylene, which can range from a yellow-white to a gray-white shade, depending on the quality and quantity of filler used.

An Ounce of Prevention
Like so many other problems in life, colorant issues are far easier to anticipate and prevent than to cure once they've occurred in molded parts. If color is important to the final performance of an application, then it should be designed in from the start via simultaneous engineering. To ensure the colorant package is properly formulated for the application, provide the color formulator with all available information on both the application and its material targets as soon as they are set.

If any of these specs change during the latter stages of the design process, inform both the resin and colorant suppliers. Changes may require a new formulation. Don't hesitate to call on the colorant provider to analyze, retest, and reformulate a color formulation to make sure it will be suitable in the end-use environment.

It's also important to inform the colorant formulator of your equipment setup, in case you need to make changes in order to optimize the resin/colorant/throughput requirements of a particular application. Finally, watch your process parameters and once the process has stabilized, note any sudden changes that may signal the beginnings of a problem.

Special care is needed when self-coloring engineering resins because a significant portion of their perceived value-and therefore cost-lies in their superior physical, mechanical, and aesthetic properties, which can be sensitive to even small compositional changes. The more important color is in a given application, the sooner the colorant provider should be involved in the design process.

 Table 1: Possible color-related problems and potential causes
. Machine/mold Process Material
  • Excessive screw and barrel wear
  • Insufficient mold venting
  • Resin temperature too high
  • Backpressure too low
  • Pack and/or hold pressure too low
  • Pack and/or hold time too short
  • Injection fill rate too fast
  • Excessive moisture in the base resin*
  • Excessive moisture in the colorant
  • Improper screw design
  • Cavity gating too small
  • Poor hot runner design (if applicable)
  • Incorrect or worn nonreturn valve
  • Required shot size too small
  • Incorrect nozzle type
  • Nozzle tip orifice too small
  • Melt temperature too high
  • Injection fill rate too fast
  • Screw speed too fast
  • Excessive backpressure
  • Hot runner temperature too high (if applicable)
  • Heat sensitive colorant formulation
  • Incorrect resin intended for the application
Poor clarity
  • Excessive wear between the screw and barrel
  • Required shot size too great
  • Poor mold surface
  • Melt temperature too low
  • Mold temperature too low
  • Injection speed too slow
  • Incompatible base resin and colorant combination
  • Material contamination
Color streaks
  • Required shot size too great
  • Resin temperature too low
  • Barrel heating element malfunctioning or out of calibration
  • Worn screw and/or barrel
  • Out of calibration or erratic colorant feeder
  • Improper screw design
  • Resin residence time too low
  • Screw speed too fast
  • Backpressure too low
  • Poor color and resin raw material mix (salt and pepper)
  • Inadequate raw material blending time
  • Not enough colorant used
  • Base resin vs. colorant melt index incompatibility
  • Incompatible colorant carrier system
Black specks
  • Screw, barrel, or nonreturn wear
  • Nozzle tip, nozzle, nozzle adapter or barrel end cap leaking
  • Mismatched nozzle tip, nozzle, or nozzle adapter rear orifice
  • Nonreturn unthreaded from screw
  • Degraded material or scale flaking off the screw and/or barrel
  • Degraded material or scale flaking off hot manifold channel
  • Required shot size too small
  • Poor purging practices
  • Barrel temperatures too high
  • Contaminated base resin
  • Contaminated colorant
  • Colorant pigments are scrubbing the screw and barrel (highly loaded TiO2 formulas)
  • Contaminated regrind or recycled materials
  • Sharp corners in the material flow path
  • Poor mold venting
  • Melt temperature too low
  • Injection speed too fast
  • Poor purging practices
  • Incompatible mix of colorant and base resin
  • Incorrect colorant carrier system
  • Material contamination
  • Required shot size too small (excessive residence time)
  • Cavity gating too small
  • Poor hot manifold design
  • Melt temperature too high
  • Injection speed too fast
  • Excessive resin drying time
  • Base resin color shift
  • Colorant out of specification
  • Colorant letdown ratio is incorrect
  • Colorant heat stability is too low
Tue, 14 Feb 2023 10:00:00 -0600 en text/html
Killexams : How to turn on or off Recommended troubleshooting in Windows 10

Microsoft has worked hard to add tons of inbuilt troubleshooting methods in Windows 10. There is one for almost one for every standard error in Windows 10. Going ahead, the team has added Recommended Troubleshooting. It allows Windows 10 to fix many critical problems on your device automatically. In this post, we will learn how to turn on or off Recommended troubleshooting in Windows 10, should you feel the need to do so.

Share Basic Diagnortics and Feedback

Microsoft Diagnostic & Feedback data offers two settings. Basic and Full. If you want to turn off recommended troubleshooting, then the only way out is to stop it from collecting complete data from your computer. So, to turn it on or off, you can choose to switch between them.

  • Navigate to Settings > Privacy > Diagnostics & feedback.
  • Choose Basic under Diagnostics Data
  • Go back to Settings > Update & Security > Troubleshoot.

You should now see a warning message which would say — Share Full Diagnostics data to get additional troubleshooting recommendations.

turn on or off Recommended troubleshooting

The message clearly states that Microsoft will only offer recommended troubleshooting based on the Full Diagnostic data which it collects. None of the advanced troubleshooting will make it to your computer.

Enable or Disable Recommended troubleshooting using Registry

Registry method to turn on or off Recommended troubleshooting

If you are comfortable with the Registry or want to turn it on or off for remote computers, here are the changes you need to make.

Open the Registry Editor by typing regedit in the Run prompt and hit Enter.

Navigate to:


Check if you have WindowsMitigation key, if yes – good! If not, right-click the left pane, and create a new key with the name WindowsMitigation.

Now under that, create a DWORD UserPreference.

Double click on UserPreference to edit the value. Set Value to 1 (On) or 3(Off) and exit.

Restart your computer to see the changes.

How Recommended troubleshooting works in Windows 10

The functionality can look into the error logs sent back to the Microsoft team, use an algorithm to set up a solution for you. They are nothing but Diagnostics and Feedback data which Windows collects and sends back to the Microsoft team. The settings of which are available under Settings > Privacy > Diagnostics & feedback.

The recommendations are only visible when you are connected to the internet. Otherwise, it will leave a warning about the same.

It’s a great move from Microsoft, but we will have to see how it works for most of the consumers.

turn on or off Recommended troubleshooting
Sat, 02 Apr 2022 10:02:00 -0500 en-us text/html
Killexams : Troubleshooting Potential Relays Killexams : Troubleshooting Potential Relays | ACHR News Thu, 16 Feb 2023 16:16:00 -0600 en text/html Killexams : VPN Troubleshooting Guide – How To Fix VPN Problems

Our content is funded in part by commercial partnerships, at no extra cost to you and without impact to our editorial impartiality. Click to Learn More

VPNs are a great tool for internet users today, and especially reassuring for those working away from their company's offices, especially on public wifi networks. When you have VPN issues, however, it can leave you without the comfort of online anonymity, and unable to access the sites and services you'd like to.

The good news is that many VPN problems can be fixed in minutes, and you don't need to be an IT expert to get back up and running. In this article, we discuss some of the most common VPN troubleshooting issues, and how to fix them.

VPN not working? Why not just try another one? Check out our VPN comparison table to see which VPNs we recommend most highly. If you'd like to stick with what you have, here are 10 fixes to resolve your VPN issues:

Having trouble with your VPN?

Are you looking for a new, more reliable provider?

1. Test Your Internet Connection

Of course, the problem may not be a VPN issue at all – it might actually be your internet connection that's the thing stopping your VPN from connecting.

Although your VPN is rerouting your internet connection through a private server and masking your IP address in the meantime, it still requires your internet connection to be active for it to work. Without this, it won't work.

Your internet and VPN may actually be both working, but sometimes switching between cellular data and a Wifi connection can mean your VPN will struggle to forge a connection to one of its servers.

Try This Fix If: Your VPN is too slow/Your VPN isn't connecting to a server.

2. Restart the VPN Software

Yes, it’s a cliche, but closing down your software can get things running smoothly again, and will fix a surprising proportion of VPN issues. If your VPN has its own program, close it down (all the way, make sure it’s not just minimized on your computer), and restart it.

If the VPN is a browser plug-in, close your browser down and restart it.

If restarting doesn't help, try reinstalling the VPN as an additional measure: This has been known to help if a VPN is slow to connect, if it crashes frequently, or if the VPN connects to the client network but does not allow the user to perform actions like opening links.

Try This Fix If: Your VPN is too slow/Your VPN is not responding at all/Your VPN won't connect.

3. Clear your Device of Old VPN Software

We know how it is – you want to make sure you have picked the right VPN software, so you may have downloaded several packages to try out. If you want to get the very best one the first time around, then just check our guide to the best VPN services, but if you’ve already trialed a handful, they may well be stopping your new chosen software from working correctly.

Try disabling, or even better, uninstalling any previous VPN software packages that you might have used, and see if this resolves your issue.

Try This Fix If: Your VPN is not responding at all/Your VPN Won't Connect.

4. Make Use of the VPN’s Help Function

VPN software providers know that at some point or other, you might get stuck. That’s why they try and ensure that there’s a built-in help function. Make sure you use it! Most are user-friendly and don’t assume you have an expert level of knowledge.

However, if you’re really confused, then do contact the VPN provider directly. How to do this will vary depending on why you go with it, with some offering phone or chat support, and others relying on email. If you’re particularly nervous about using a VPN, then it’s worth opting for one that can answer quickly.

Try This Fix If: Your VPN is not connecting/Your VPN won't let you log in.

5. Make Sure Your VPN is Up To Date

VPN software is regularly updated. Some of these take the form of quality-of-life tweaks to make the program easier to use, but others will be essential for the day to day functionality of the VPN, so it’s important to make sure that you don’t ignore update requests.

The easiest way to find out if your software is up to date is by checking the version you’re running against the version number on the provider’s site. You can usually find this information in the About section of your VPN software, as demonstrated here in ExpressVPN.

Try This Fix If: Your VPN is not connecting/Your VPN is too slow.

6. Change the VPN Server

VPNs offer literally hundreds of servers to connect to, but they might not all be functioning correctly. There can be several reasons for this – they could be overloaded with traffic, temporarily down, or even blacklisted by the service you’re trying to use.

Luckily VPN troubleshooting is made easy by the fact that almost all VPN providers will let you choose to connect to different servers, so give another one a go. Don’t worry if you’re using a certain country’s location to access content – any VPN worth its salt will offer a multitude of servers in the same country, so you shouldn’t have any issues finding another.

Try This Fix If: Your VPN is too slow/Your VPN says it isn't connected, but your IP address isn't hidden/the internet service your are trying to access is blocking your VPN.

 7. Connect Using a Different VPN Protocol

If you’re struggling to connect, the VPN problem could be its protocol. A protocol is essentially a network that is used to exchange data – the most common example of this is HTTP, which you’ll be familiar with, which stands for Hypertext Transfer Protocol – and precedes every website you look at in your browser.

If there are issues with your connection, playing with the protocol settings can be the solution. Experiment with changing the protocol in the settings to see if this resolves your issue. It could even lead to a faster connection.

Needless to say, it’s the premium, paid-for services which will offer the best help options.

Try This Fix If: Your VPN is too slow/Your VPN says it isn't connected, but your IP address isn't hidden.

8. Check Your Firewall

Firewalls check the data that comes in out of your connection, and they can be very protective of what traffic makes it to your computer (and rightly so – it’s their job, after all).

Some firewalls create VPN issues, so as an experiment, try temporarily disabling your firewall to see if this has a positive effect on your VPN connection – don’t forget to turn it back on when you’re finished checking though!

Try This Fix If: If there's no obvious VPN problem, but your VPN is not Responding.

A unique open source option


  • Free, open-source VPN
  • Boosted privacy and secure browsing
  • Supported by a developer community


  • Can lead to poor speeds when in use
  • Too technical and complex for first-timers
  • Can be blocked by business proxies

11. Flush Your DNS Cache (Computer Only fix)

If nothing has worked yet on your quest to solve your VPN issues, you may want to try flushing your DNS cache. Why might you need to flush your DNS cache? Well, VPNs allow you to bypass your ISP's DNS, but your operating system may inadvertently be using cached DNS settings from when you weren't using your VPN, which can cause a VPN problem.

To flush your cache on a Windows computer, type “cmd” into the system search box in the bottom left-hand corner of your screen. Next, right-click on “command prompt” and select “Run as Administrator”. After a new window opens, enter “ipconfig/flushdns” (without quotation marks) and press “Enter” on your keyboard.

For devices running macOS, click the Spotlight search button and type in “Terminal”. When the Terminal application appears, double-click it. When the terminal is open, enter this command “sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder” (without quotation marks). After that, you just have to enter your Mac's password when prompted, which will clear the DNS.

As you can probably tell, this is a relatively advanced VPN troubleshooting tactic compared to the others, so we'd recommend trying our previous suggestions first.

Try This Fix If: All the above options have failed.

VPN Troubleshooting: Why is my Netflix VPN not Working?

One of the most common VPN use cases is unblocking Netflix content only available in certain countries. Netflix geo-restricts a lot of its movies and films for a variety of reasons. Certain releases may be banned in some countries, or Nextlif simply might not have the rights to show a given film in a specific territory yet.

If your Netflix VPN is not working, then we'd recommend attempting all of the VPN troubleshooting techniques listed in this article to see if your software or your internet connection is the problem. If you've eliminated those possibilities, unfortunately, the reason your Nextlix VPN is not working is probably that Netflix has banned the VPN IP address you're using to attempt to connect to the site.

Don't worry, that's pretty normal; Netflix is in the business of tracking down IP addresses it can tell belong to VPNs and banning them. If you think this might be the reason behind your Netflix VPN not working, then follow these steps:

  1. Connect to a different VPN server based in the same region/country.
  2. If that fails, Connect to a VPN server based in another region where the movie/film you'd like to watch is available.
  3. If that fails, you will need to look into switching to a streaming-optimized VPN.

VPN Troubleshooting: Why is my VPN so Slow?

Remember, because you're funneling all of your requests and data through an encrypted tunnel and into a private VPN server before it reaches the internet, you're asking it to make a longer journey – so, it's natural that a VPN will affect your internet speed. However, if it's a decent VPN, the difference should be almost negligible. Reasons your VPN might be slow include:

  • Poor internet connection
  • Routing too much of your data through the VPN
  • Too many people connecting to the same server
  • Poorly configured VPN settings

If your VPN is slower than you'd expect, here are a couple of things you can do to try and speed it up:

  • Connect to a different server provided by your VPN provider
  • Connect to a server nearer to your physical location
  • Switch from cellular data to a nearby Wi-fi connection
  • Review your VPN settings

If your VPN provides a split-tunneling function, you'll be able to route some of your application traffic through your VPN client and some through your normal network. If your VPN is slow, you could explore using this function to speed up your experience on specific apps.

VPN Troubleshooting: Do VPNs Work on iPhones?

Right now, it's difficult to say. Although many VPNs have clients you can get and use on your iPhone, recently a vulnerability that leaks VPN traffics on iPhones was found to still be present in iOS 16 in 2022, meaning it's likely a VPN problem for all iPhones.

Apple has been aware of this VPN issue for several years. Proton VPN notified the company that unencrypted traffic was leaking out of users' VPN tunnels, two years ago. This issue was brought to the attention of Apple by Mullvad VPN again in 2020, while in 2022, security researcher Michael Horowitz found the vulnerability alive and well in iOS version 15.6.1.

Now, some researchers claim the vulnerability still exists in iOS 16, the latest iteration of iOS. Researchers at Mysk, for instance, have shown that “iOS 16 does communicate with apple services outside of the VPN tunnel.”

Apple is yet to comment on this and, all in all, the jury is still out. Although millions of people are still using VPNs on their phones despite this news, if you can use it on a different device, in light of this news, we'd recommend doing so.

Next Steps for VPNs

Now that you've sorted out your VPN connection problems, it's worth considering that maybe you don't have the right VPN for your particular needs. With a wide range of options on the market, taking a look at your alternatives could save you a lot of time in the troubleshooting department down the line. has done extensive research on the best cheap VPNs on the market, so you can get an honest look at some of the features, pros, and cons of each. Then you can decide whether or not your current VPN is getting the job done.

Price From
Lowest price for single month subscription to cheapest paid tier. Other plans are available.
Click to find the latest offers, deals and discounts from the VPN provider

$2.75/month (3-year plan)

Powerful features and security, but a bit technical. Some massive savings currently available.

A safe, simple, outstanding VPN

Outstanding value, with an advanced VPN app

Good VPN privacy at good speeds

A decent option for expert users

A user-friendly VPN, let down by some speed loss

Superb features, but at a higher cost

A powerful tool for expert users

7,000 servers (90+ countries)

30-day money-back guarantee

30-day money-back guarantee

VPN Troubleshooting: Frequently Asked Questions

If you're panic that your VPN might not be working, there's a really easy way to check. Simply head over to – or any other site that will tell you your IP address. If the website is saying that your IP address is in the location you're actually situated in – then we're sorry to say that your VPN is not working. If the website says you're in the location of the VPN server you're connected to, then your VPN is working.

The WireGuard protocol is a high-speed open-source communication protocol that is now provided by many mainstream VPN providers. It runs on about 4,000 lines of code, instead of the hundreds of thousands of lines of code used to build other VPN protocols, which culminates in a faster, smoother, and overall steadier VPN experience. Fewer lines of code also mean it is easier to audit for security vulnerabilities.

The best VPN, according to our tests, is NordVPN. Not only is it one of the fastest VPNs currently available, but it also has over 5,000 servers to choose from across 59 countries. NordVPN equips its users with the best features on the market, including Threat Protection to protect you from malicious websites, obfuscated servers that hide your VPN connection, and split tunneling, so you can funnel some traffic through your VPN connection and some outside of it. NordVPN has a strict no-logs policy and will never record any of your internet activity.

There are a number of reasons why your VPN might not connect. Start by testing whether your internet connection is working without a VPN – if it isn't, then the problem may be that, rather than your VPN. If your internet is working, try a different VPN server pr protocol to see if it's simply a problem with either of those two aspects of your VPN. If the issue still persists, check you don't have another VPN active on your device, and then restart your VPN. After that, the best option is to contact your VPN's customer support email.
Mon, 01 Oct 2018 23:22:00 -0500 en-US text/html
Killexams : App Troubleshooting Help Needed on Chromebook Best option is to report it to the people who make the app, most apps have a feedback option on their app store page. The developer will either fix the issue for you or help you figure out what is wrong.

Aside from that, you could uninstall the app, reboot and then install it again.

Sat, 21 Jan 2023 05:59:00 -0600 text/html
Killexams : Solved! What to Do When Your Dishwasher Is Not Draining
dishwasher not draining

Q: I just opened the dishwasher door to find the bottom of the unit filled with dingy water. My first thought was that the cycle didn’t finish so I ran the dishwasher again, but that didn’t help. Why is my dishwasher not draining? Is this a do-it-yourself fix, or do I have to call a plumber?

A: You did the right thing running your unit a second time. If it gets inadvertently shut off during a cycle, there’ll be standing water in the dishwasher bottom when you open it. When that smart move doesn’t solve the issue, the problem lies elsewhere. Dishwasher service calls are common in the plumbing industry, but fortunately, the fix to a dishwasher not draining is often something simple you can do yourself. Before you call a pro, troubleshoot your dishwasher by following these steps.

Determine the type of dishwasher drain connection you have.

The first step in troubleshooting a dishwasher that’s not draining is pinpointing the type of drain connection beneath the sink. Open the cabinet and look at the configuration of the corrugated dishwasher drain hose and how it connects to the sink drain. The following drain connections are the most common.

  • High loop to disposal: In this configuration, the dishwasher drain hose will enter the cabinet from the dishwasher—loop to the top of the cabinet, where it’s held in place with tape, a string, or a chain—and then connect to the garbage disposal.
  • High loop to drain: If no garbage disposal is connected, the dishwasher drain hose should still have a high loop, but it will then connect to the drain pipe. The connection must be before (above) the P-trap on the drain line. Sewer gases can enter the dishwasher and leave a stinky smell if it isn’t.
  • Air gap to disposal: In this configuration, the hose runs to the top of the cabinet just as in the high loop, but instead of having a tape or chain to hold it in place, the hose connects to a fitting at the back of the sink. If the dishwasher drain connection has an air gap, a small cylindrical knob will be installed on the sink’s top to allow air to enter and prevent dirty sink water from draining back to the dishwasher. In essence, an air gap is like a dishwasher overflow that prevents air locks in the hose.
  • Air gap to drain: This is the same configuration as air gap to disposal, just minus a garbage disposal. The hose will run to the air gap and then connect to the drainpipe before the P-trap.

Consult a pro

Get free, no-commitment repair estimates from licensed appliance technicians near you.


Run your garbage disposal.

The drain hose from your dishwasher empties into the garbage disposal drain. If the disposal unit contains unground food, or food sludge has settled in the drainpipe below the disposal, it can prevent even the best dishwasher from draining properly. Sometimes, running the disposal is all it takes to get the dishwasher draining again.

In fact, it’s a good idea to get in the habit of leaving the water on and letting your garbage disposal run an additional 15 seconds after the food is gone. This clears all remaining food that might otherwise remain in the P-trap drain beneath the disposal.

RELATED: 9 Tips for Keeping Your Garbage Disposal in Top Shape

Remove standing water in the bottom of the dishwasher.

If running the garbage disposal doesn’t help (or you don’t have one), it’s time to drain the water in your dishwasher so that you can take a closer look at what could be causing the problem. Place absorbent towels around the base of the dishwasher and then remove the bottom dish basket by simply sliding it out. With the basket out of the way, use a plastic cup to scoop the dirty, foul-smelling water into a bucket for disposal. When the water level is too low to scoop, use towels to sop up the last bit in the bottom of the machine.

Clean your dishwasher air gap.

In most cases, a drain connection with a dishwasher air gap is the least likely to have problems, but whether yours has one depends on local building codes. Some communities require air gaps, but others require only a high loop under the sink cabinet in the hose. If your dishwasher has an air gap, it will typically be located next to your kitchen faucet (in the photo at right, the air gap is to the left of the spray nozzle).

Occasionally, an air gap can become clogged with debris, which can prevent the dishwasher from draining correctly and leave standing water in the dishwasher. To investigate, twist the air gap counterclockwise to remove it, and check the inside for gunk. Clean the air gap with water and a stiff brush, replace it, and run the dishwasher cycle again.

Clear up detergent mishaps.

Dishwashers are designed for use with automatic dishwasher detergents that clean without producing suds. In the course of a hectic day, it’s easy to accidentally squirt regular dishwashing liquid into the unit, which can easily create enough suds to prevent proper draining. The same problem can occur if you run out of automatic dishwasher detergent and substitute laundry detergent in a pinch. Guilty as charged? Simply bail out the tub as described above and run the cycle again, this time using the correct dishwasher detergent.

RELATED: Solved! 4 Reasons Why Your Dishwasher Isn’t Drying

De-gunk the drain basket.

The drain basket is often the source of a smelly clogged dishwasher. It’s found at the base of your dishwasher, usually below the bottom rack. Its cover often resembles an upside-down basket, which either snaps off or is held in place by one or two screws. (If the bottom of your machine doesn’t look like this consult your owner’s manual, which you can often get from the manufacturer’s website.)

Remove the cover, and check for food buildup in the basket beneath. Use your hand or a spoon to remove any debris, replace the cover, and run the dishwashing cycle again.

Note: If you find a lot of food debris in the drain basket, prevent future clogs by pre-rinsing your dishes. Most dishwashers manufactured today feature macerators that grind bits of soft wet food, but they don’t have the power of a garbage disposal. Even if your dishwasher’s manual says you needn’t pre-rinse the dishes, do so anyway to avoid repeatedly cleaning the drain basket.

Consult a pro

Get free, no-commitment repair estimates from licensed appliance technicians near you.


Check the dishwasher drain hose for kinks.

A dishwasher drain hose—the lightweight, ribbed plastic hose that connects from the dishwasher’s drain pump to the garbage disposal (or to an air cap)—can prevent water from draining if it is kinked. If something large or heavy was shoved under the sink it might have hampered the dishwasher hose, so explore the area and locate the hose. If it is kinked, try straightening it out manually.

Unfortunately, once a drain hose kinks, it tends to happen again in the same spot. If this continues to happen, replace the drain hose. (It’s a simple enough DIY task—keep studying for details.)

Examine the drain hose for clogs.

If the hose isn’t kinked, it could still be clogged with food sludge or debris. To check for a clog, you’ll need to remove the lower front panel of the dishwasher and locate the spot where the ribbed hose attaches to the drain pump.

First, unplug the dishwasher: While you shouldn’t come in contact with any wiring, the general rule of thumb when working on appliances is to unplug them first. Place old towels under the unit and remove the lower front panel. Many panels snap off but, depending on your model, you may have to remove a screw or two. Disconnect the hose from the pump (if you’re unsure where it is or how to disconnect it, consult your owner’s manual).

To check the hose for clogs, simply blow through it. If air won’t pass through, you’ve got a clog. If the clog is located at either end of the hose, you can try to carefully remove it with a screwdriver or other thin implement, like a straightened out wire coat hanger.

If the clog is not located near the end connected to the pump, remove the hose where it connects to the garbage disposal or air cap to check for a clog on that end. If the clog is lodged deeper, you’ll probably have to replace the entire hose. Don’t try to clear the clog with a plumber’s snake. Dishwasher hoses aren’t designed to withstand the tool’s cutting motion and can be easily punctured.

Replace the drain hose.

For recurring kinks or a clog that you can’t remove, you’ll have to replace the entire hose. Call a plumber if you’re not comfortable trying this yourself. A pro could easily charge a minimum of $150 for a house call, so you’d save a bundle making the repair yourself. First, you have to unplug the dishwasher and slide it out from under the countertop.

Next, disconnect the old hose from both the pump and the garbage disposal (or the air gap), and attach the new one in the same manner. Consult your owner’s manual first to ensure that you purchase the correct replacement hose, and for any specific instructions on how it attaches to your appliance.

RELATED: 5 Reasons Your Dishwasher Is Leaking (and How to Fix It)

Call the plumber.

When we’re faced with a dishwasher not draining, one of the above techniques will usually solve the problem. If you have tried all these tips to no avail, the problem could lie in a faulty dishwasher pump, or in the dishwasher’s timer or motherboard. Replacing these specialty parts should only be done by a licensed plumber, so if you’re in that situation, call a plumber.

Final Thoughts

Most of the time, when you find a dishwasher not draining, the remedy is simple and inexpensive. It’s likely the result of a full garbage disposal that won’t allow the drain water to enter from the machine, so it backs up in the bottom of the dishwasher. Barring that, the problem is probably a kink in the drain hose, or a clog in the hose, the drain, or the air gap. When determining how to drain the dishwasher, the homeowner rarely needs to call a plumber if they follow the above steps.

Depending on the brand of dishwasher, you’ll find that most machines don’t have macerators (grinding disposals). For this reason, putting dishes in the dishwasher that still have chunks of food is a sure recipe for a clogged drain. Rinse your plates before washing them!


Since it’s one of the handiest appliances in the home, the dishwasher is easily taken for granted—until it stops working. If dirty water is standing in the bottom of the machine after the cycle completes, the dishes will also be dingy, and the machine might smell bad. When the dishwasher won’t drain, a few questions are in order.

If the dishwasher won’t start, make sure the breaker that serves the electrical circuit hasn’t flipped off. Then, check to ensure the machine’s plug hasn’t become dislodged from the electrical outlet. Other things to check are whether a child safety lock has been activated and whether something is keeping the machine’s door from closing tightly.

Q: How do you clean a dishwasher drain hose without removing it? 

You might be able to clean a dishwasher drain hose by pouring 1 cup of baking soda and 1 cup of white vinegar in the machine’s drain and then letting it sit for up to 15 minutes before flushing with hot water and then running a rinse cycle. This usually only works for clogs in the hose near the drain.

Q: How do I get rid of standing water in the dishwasher?

Try running the disposal and rerunning the dishwasher cycle. If that doesn’t remove the water, bail it out manually and proceed with the troubleshooting sequence.

Q: Will Drano ruin a dishwasher?

It certainly could. Drano is caustic and can eat through a plastic drain hose and damage the machine’s motor.

Q: Can you put baking soda and vinegar in dishwashers?

Yes. Mix equal parts of baking soda and white vinegar and put the solution in the drain for a few minutes before running a cycle. When used regularly—every month or so—this solution can help keep clogs from forming.

Consult a pro

Get free, no-commitment repair estimates from licensed appliance technicians near you.

Sun, 06 Nov 2022 03:09:00 -0600 en text/html
Killexams : Android Auto problems and how to fix them
Android Auto in Volkswagen ID.4 Center Console Interaction with Drivers Console

C. Scott Brown / Android Authority

Android Auto is one of the best apps you can get for your car. It’s already available on your Android phone, and if your car supports it, you have a quick way to access Google Maps and music apps, make and receive calls, and reply to messages (with your voice) while you’re out and about. Android Auto makes life much easier on the road. When it works. Unfortunately, one of the most common phone problems users complain about has to do with Android Auto. Here’s a look at some Android Auto problems and how to fix them.

Read more: What is Android Auto?

Editor’s note: Some of these steps were put together using a Pixel 7 Pro running Android 13. Some steps might be different depending on your hardware and software.

Does my phone, stereo, or car support Android Auto?

Android Auto in Volkswagen ID.4 Start Android Auto

C. Scott Brown / Android Authority

Let’s start with the basics. Not all phones, cars, or stereos support Android Auto. There are also location restrictions, so you won’t be able to use Android Auto from unsupported countries.

Android Auto requires that your phone runs at least Android 8.0, and that’s for a wired connection. Those wanting to use Android Auto wirelessly will need an active data plan, 5GHz Wi-Fi support, and at least Android 11. There are some exceptions. Google and Samsung phones can get away with Android 10. Samsung Galaxy S8, Galaxy S8 Plus, and Note 8 handsets can do with Android 9.0.

You can download the app from the Google Play Store. For any phone with Android 10 or newer, Android Auto is already baked into your phone’s Settings menu.

Let’s move on to cars and stereos. You can check the car and third-party stereo compatibility on Google’s official list. The list of vehicles shows the oldest model that supports Android Auto, and it’s safe to assume that latest cars from these manufacturers support the service. Most latest releases also support Android Auto Wireless. But it’s best to check with the seller first to ensure the vehicle you are interested in supports the service.

Unfortunately, if the car or stereo doesn’t support Android Auto, you won’t be able to use it on just your phone. Google removed the Android Auto for phone screens feature with Android 12. You can still download and install the app on older devices. But with any phone running Android 12, you will have to rely on the Google Assistant Driving mode.

Android Auto availability also depends on your location. The app is available in 46 countries, and not all of them support Google Assistant while using Android Auto. You can find the complete list of supported countries here. Scroll down to the FAQ and look for Is the Android Auto app available in my country?

Similarly, if you live in an unsupported country, there isn’t much you can do other than wait (very patiently).

The classic solution of turning it off and back on!

It’s one of the most common troubleshooting tips: restart it! I’ve found the same applies to Android Auto not working. First, try unplugging your phone and plugging it back in. This often fixes the problem. If that doesn’t work, turn the phone off and back. Lastly, you can try turning the car off and on again.

How to restart your Android phone:

  1. Press the Power and Volume Up buttons simultaneously.
  2. Tap on Restart.

Android Auto is not working on recently purchased phones

Android Auto in Volkswagen ID.4 Connecting With Smartphone

C. Scott Brown / Android Authority

Phone makers make it easy to transfer files, apps, and settings from an old phone to a new device with apps like OnePlus Switch, Samsung Smart Switch, and more. Users say that using these methods to set up their new phones often causes problems with Android Auto. There are a couple of solutions we can recommend.

Uninstall and update the Android Auto app:

  1. Open the Google Play Store.
  2. Search for Android Auto.
  3. Tap on the Android Auto app page.
  4. Hit the Uninstall button and confirm the action by tapping on Uninstall again. Let the process finish.
  5. Tap on Update.
  6. Try using Android Auto again.

Clear the Android Auto app cache and storage:

  1. Open the Settings app.
  2. Go into Apps.
  3. Tap on See all apps.
  4. Find and select Android Auto. In newer devices, the app is moved to the system and might appear as
  5. Go into Storage & cache.
  6. Tap on Clear storage and Clear cache.

Check Android Auto app settings

Settings logo on Android phone stock photo 1

Edgar Cervantes / Android Authority

The Android Auto app has various settings that might be deactivated, which can stop the app from working when connected to a car.

Check the Android Auto settings are correct:

  1. Open the Settings app.
  2. Go into Connected devices.
  3. Tap on Connection preferences.
  4. Hit Android Auto.
  5. Select Start Android automatically and pick Always.
  6. Toggle on Start Android Auto while locked.
  7. Enable Wireless Android Auto if your car and phone support it. If it doesn’t, or you want to use a wired connection, disable this setting instead.
  8. Tap on Previously connected cars at the top of the settings and ensure your vehicle isn’t accidentally on the Rejected cars list. Enable Add new cars to Android Auto. However, in some cases, if you plan to use the same car every time, users say that disabling this setting helps fix connection problems.

Android Auto problems with the USB cable

Android Auto in Volkswagen ID.4 Google Maps Navigation

C. Scott Brown / Android Authority

A lot of Android Auto connection problems occur because of a faulty cable. If you see frequent disconnections or Android Auto isn’t loading at all, the cable might be the problem.

Potential solutions:

  • Google recommends using a cable under 1 meter (3 feet) long. It’s also best to use the cable that comes with the phone. If you use a third-party cable, make sure it is USB-IF certified.
  • Check the cable to see if it works with another phone or car. If not, it’s likely a faulty cable that you will need to replace.
  • A March 2022 Android Auto update (version 7.5.121104) added a USB startup diagnostics tool to tell you if you are using a suitable cable. After connecting the phone to your car, open the Android Auto Settings, tap on Connection help, and go to USB startup diagnostic.
  • It could be a settings issue. The phone should automatically recognize when you are trying to use Android Auto. If it only charges the phone when you plug it into your car, open the notification drawer. Tap on USB settings and select Data transfer/Android Auto.

Problems with Android Auto Wireless

Android Auto in Volkswagen ID.4 App Selections

C. Scott Brown / Android Authority

You don’t have to worry about carrying a cable around if your car supports Android Auto Wireless (check with your car manufacturer). However, plenty of users face problems with connecting to the wireless feature.

Make sure Bluetooth is enabled:

  1. Open the Settings app.
  2. Go into Connected devices.
  3. Select Connection preferences.
  4. Hit Bluetooth.
  5. Toggle Use Bluetooth on.

If you are facing problems with Android Auto Wireless, users say that setting up a wired connection first seems to do the trick. Plug the phone in with a cable and set up Android Auto. Once the connection is established, Android Auto should work the next time wirelessly. Turn off your car, unplug the phone, and try to use Android Auto Wireless.

Blurry, pixelated, or blank screen

Some users say that while Android Auto seems to connect and the Google Assistant works as expected, they see a blurry, pixelated, or blank screen.

How to increase the Android Auto video resolution:

  1. Open the Android Auto app.
  2. Scroll to the bottom and tap on the Version section to display the Version and permission info.
  3. Tap on this section multiple times continuously.
  4. You’ll be asked if you want to allow development settings. Hit OK.
  5. Tap on the three-dot menu icon in the top-right corner.
  6. Open Developer settings.
  7. Go to Video resolution.
  8. Set the resolution to the highest option available.

Fixed/known Android Auto problems

Android Auto in Volkswagen ID.4 Google Assistant Command

C. Scott Brown / Android Authority

With a mix and match of phones, cars, and third-party stereos, it’s difficult to pinpoint what is causing Android Auto problems and offer solutions beyond general troubleshooting. Google continuously updates Android Auto and fixes issues as they come up. You should also report any problems you face to let Google know.

Recent fixed problems (January 2023)

  • Amazon Music plays the wrong song.
  • Unable to navigate/scroll when using Google Maps.
  • Android Auto uses phone speaker for calls instead car speaker.
  • “App isn’t compatible” error on Pixel 7 devices.
  • Missing weather icon on the top right of the car display.
  • “Looking for Android Auto” notification on Android 13.
  • Navigation doesn’t start via voice command.
  • Google Assistant doesn’t make outgoing calls.
  • Connectivity issue on Samsung Galaxy Z.

Known issues

  • Screen turns black when saying “Hey Google.”
  • Assistant does not read incoming messages.
  • Pandora app automatically starts on connection.
  • Android Auto randomly disconnects on Pixel 7 phones.
  • Can’t connect to Samsung S22 Ultra.
  • Android Auto does not connect post Android 13 update.
  • Android Auto does not connect post MIUI 13 update.
  • No sound from Google Assistant.

How to send feedback/bug reports

Open the Android Auto settings page and tap on the three vertical dots at the top right corner. Go to Help and feedback > Send feedback. You can also post your problems on the Android Auto community page.

Mon, 23 May 2022 19:07:00 -0500 en text/html
Killexams : Troubleshooting Respondus LockDown Browser

Operating System and Security Settings

LockDown Browser
  • Shares properties with IE if on Windows machine
  • Shares properties with Safari if on a Mac.
  • Security Settings in browser

  • 10* and 8. Windows 10S is not a compatible operating system.
    *  Includes x86 32 and 64bit processors and ARM 64bit processors using x86 emulation.
  • 200 MB of free hard disk space
  • IE has to be set to default security levels
    • Anything higher and JavaScript cannot be ran and cookies won’t be sent or received causing login and test taking errors.
  • IE has to be 7.0 or higher
  • If IE has some sort of infection or not working properly, the LockDown Browser could error.

  • MacOS 10.12 to 11.1
  • iOS: 11.0+ (iPad only). Must have a compatible LMS integration.
  • 200MB permanent space on the hard drive.
  • Safari must be in proper working order. 

If you experience errors while taking a test through the LockDown Browser, check your security settings in IE and the overall functionality of IE. IE should be reset to default security levels, and the test should be tried again.

The following tips may help to correct other problems encountered with Lockdown Browser.

Important Note: Non-testing Purposes

Only use Respondus LockDown Browser for testing purposes.

If you attempt to use the browser to access additional course content, like lecture notes or worksheets, it may cause the program to encounter a problem and freeze or close. This usually occurs when the content you are attempting to access is a Word, PowerPoint or Adobe Acrobat related file. The browser cannot open the external program needed to run these files because of the browser’s restricted nature and it creates an internal error with the software. If you need to view these files, please use a regular browser like Mozilla Firefox.

Problems Downloading and Installing the LockDown Browser

If you are having problems installing LockDown Browser on a Windows system, we recommend the following additional steps:

  1. Directly log into a system as a local administrator with full rights. Do not use “Switch User” or a “Remote Access” connection.

    Important Note:

    Logging in as a non-administrator and then using “Run as Administrator” may not set the correct permissions.

  2. Temporarily disable all security software. Contact the IT Help Desk for additional assistance in disabling your security software.
  3. Download Respondus LockDown Browser. Do not “Google” for a link because these are campus specific.
  4. When you start running the installer and get to the large button “LockDown Browser Click to install”, instead click the link “Problems with the installation program? Click here”. You will be presented with an option to extract the files to a location of your choosing.
  5. Go to the folder you extracted the files and run “setup.exe”.
  6. Start the LockDown Browser to verify installation and then quit the LockDown Browser.
  7. Re-enable any security software.

Because the LockDown Browser is a shell that sits on top of an Internet browser (Internet Explorer for PC users and Safari for Mac Users), we recommend students access their course with either Internet Explorer or Safari and take a non-LDB enabled practice quiz to resolve any settings and media plug-ins prior to taking a test with LockDown Browser.

For Windows systems, we suggest relaxing any security settings to “medium”, add “LockDown.exe” as a trusted application and “*” address as a trusted site in any security software.

Using LockDown Browser on a Wireless Connection

We strongly recommend using an Ethernet (wired) Internet connection with a speed of at least 512 Kbps or higher while taking your test in LockDown Browser. If you use a wireless, USB modem, laptop connect card, or mobile hotspot connection during an exam, you are more likely to run into problems due to dropped/interrupted connections to the Canvas server. This is because the Canvas server is more bandwidth intensive (especially during exams) than normal Internet surfing.

If you lose your Internet connection during the exam, it will lock up the browser and not allow you to save answers, move on to other questions, submit or exit the exam. Ethernet connections are the most stable connection to the Canvas servers. If you have a router, plugging directly into it when taking exams will reduce the chances of connection interruptions.

Permissions Errors in LockDown Browser

If you are getting an error when you attempt to open the LockDown Browser that says “You may not have the appropriate permissions to access the item”, it may be an issue with the permissions on your system or antivirus software.

Respondus LockDown Browser uses the same HTML engine, system components and settings as Internet Explorer (Windows) and Safari (Macintosh). Basically, LockDown Browser provides a custom interface for the Internet Explorer (Windows) or Safari (Mac) browsers that are already installed.

We recommend completely uninstalling the software and doing a new installation while directly logged into the system as a local administrator with full rights (see instructions above for full details).

Link is Blocked Error

This occurs when there is a second level link being accessed from a primary level link. However, link blocking usually does not occur until the student enters a quiz and starts accessing links within a quiz. Usually, this comes from configuration issues with the underlying Internet Explorer browser components.

To resolve this issue, please try the following:
  • Start Internet Explorer and first go to Tools.
  • From the Tools menu, select Internet Options.
  • Inside the Internet Options dialog box under the General select Browsing History.
  • Hit Delete to clear the browser cache and related areas.
  • Finally, if you are running any third-party toolbars or add-ons, remove them from Internet Explorer.

LockDown Browser and Other Programs

The LockDown Browser is programmed to detect when conflicting programs are still running and will request that you close these programs. Some programs like the Dell Dock and Google Toolbar run as a background process on your computer and will have to be shutdown before you can proceed in the LockDown Browser. You can usually turn these programs off through the task tray or, in the case of the Dell Dock, by right clicking on the application and clicking Exit.

In some rare instances, these programs running in the background can cause the LockDown Browser to lock up or stop responding. Programs that use Java or the Internet such iTunes and other media managers, file sharing agents like Bittorent, and instant messenger applications have a higher risk of causing the LockDown Browser to lock up. It is best to close every program on your computer before starting the LockDown Browser.

LockDown Browser and Pop-Ups

If the LockDown Browser stops responding before you start an test or if you see a blank page that fills the computer screen, this could be due to security windows that have popped up behind the LockDown browser. If you have not started the exam, close the browser and address the security pop-up windows. You should be able to reopen the browser without issue. However, if you have started the exam, the only known workaround is to restart your computer and address the pop-up windows before beginning the exam.

LockDown Browser Stops Responding

If you lose your Internet connection while taking an test or if you have outdated and/or multiple Java installations, the LockDown Browser and your computer may stop responding or freeze. Currently, the only way to resolve this issue is to do a hard shutdown (i.e. unplugging all power from the computer including power cables and/or batteries if you are using a laptop). If you are missing your Start Menu, Task Bar or are unable to access the Task Manager after doing a hard reboot, you can restore these applications by restarting the LockDown Browser and exiting the software properly.

Depending on your system, this could take several minutes and will cause you to lose time on the exam. In most cases, as long as the time has not expired, it should let you back into the exam. As soon as you have completed the exam, immediately e-mail your instructor to let them know what happened.

LockDown Browser Updates

Occasionally, Respondus will release a new version of the LockDown Browser. When a new version of LockDown Browser becomes available, the system will prompt you to update your installation of the software.

Whenever you update your LockDown Browser, you may also want to do the following:

  1. Make sure your system is up-to-date by installing all necessary system updates. You will also want to make sure you have the latest version of Internet Explorer for Windows users and Safari for Mac users.
  2. Make sure you only have one version of the most latest Java installed on your system.

Important Note:

Macintosh users should be aware that Apple supplies their own version of Java for all operating systems prior to OS X 10.7 Lion. For Macintosh operating systems prior to Lion, use the Software Update feature (available through the Apple menu) to check for Java updates.

Thu, 31 Mar 2022 08:07:00 -0500 en text/html
Killexams : The New York Times Books No result found, try new keyword!By Nikole Hannah-Jones “Not a generically boring office job, but something terribly specific that we don’t normally get to hear about,” says the author, whose new book is “I Have Some Ques ... Thu, 16 Feb 2023 18:02:00 -0600 en text/html Killexams : Troubleshooting A Symlink — A Whodunnit For The Git Record Books

While I normally sport the well-worn fedora of a hard-boiled sysadmin, Sunday mornings I swap that neo-noir accessory for the tech-noir: a pair of pro headphones. This is the tale of the collision of those two roles. An educational caper, dear reader. You see, my weekly gig is to run a Facebook Live Stream, and Facebook just recently began enforcing a new policy: all video streams are required to use encryption. We have Fedora installed on the media machine, and use Open Broadcaster Software (OBS) to stream. It should have been easy to update the stream settings. I made the necessary changes and tested it out — no luck. The error message was less than helpful: “Failed to connect to server”. With a sigh, I took off my headphones, put my sysadmin hat on, and walked out into the digital darkness. It was time to get back to work.

What the RTMPS?

Some terms, before we dive in. RTMP is the Real Time Messaging Protocol, originally developed by Macromedia. Thanks to Adobe, a version of RTMP is now an open specification, and many video streaming services now use it to transport live audio and video across the internet. RTMPS is simply the encrypted version, where RTMP is wrapped inside a TLS/SSL connection. TLS, Transport Layer Security, is the same protocol that powers HTTPS. TLS does depend on your machine having a good copy of the certificate bundle, a collection of public keys that are considered to be trustworthy.

How does one go about trying to fix this sort of problem? A good first step is to get a more useful error message. Running OBS from a command line lets us see all the extra output messages that are usually invisible. Below I’ve cut out all the extra messages, to highlight the failing connection attempt.

info: [rtmp stream: 'simple_stream'] Connecting to RTMP URL rtmps://
info: RTMP_Connect1, TLS_Connect failed: -0x7680
info: [rtmp stream: 'simple_stream'] Connection to rtmps:// failed: -2
info: ==== Streaming Stop ================================================

Now we’re getting somewhere. The failure is specifically in the TLS connection, which we could have guessed. We also get an error code. Quick note on trying to search for that error: Google will interpret the leading dash as an indicator that you want results that don’t include that search term. Surrounding it in quotation marks, "-0x7680" is the way to get useful results.

How to Narrow Down the Cause of an Error

Searching for that error number will bring up two interesting hits. One is the thread in the OBS forum where those of us facing this problem have been discussing it. The other hit is the mbedtls documentation, where an error with this code is defined. It’s possible that it’s a false positive, but since we’re troubleshooting a TLS issue, it’s likely related. That error is MBEDTLS_ERR_SSL_CA_CHAIN_REQUIRED, and is described as “No CA Chain is set, but required to operate.”

So what’s next? We’ve learned a bit, but still don’t have any answers, so let’s dive into code. My standby quick-and-dirty debugging technique is to add printf() calls to help follow code execution, but where to start? We have a breadcrumb in the program output, “RTMP_Connect1”. Searching the OBS codebase on Github lands us at a function with that name. Partway through the function, we can see the command to print the log message that brought us here.

The error message indicates that a CA chain isn’t loaded. That sounds like an initialization problem. Perhaps that term “chain” is used in the OBS source. Searching our suspect file returns 18 hits, 17 of which are in a function named RTMP_TLS_LoadCerts(). I spent some time chasing down the execution flow of the RTMP connection, even making a sketch of when each function gets called. The code led me back to RTMP_TLS_LoadCerts(). That function has quite a bit of code in it, but we can safely ignore the parts that are specific to Windows or MacOS. There is an obvious line that should load system certs.

if (mbedtls_x509_crt_parse_path(chain, "/etc/ssl/certs/") &< 0) {
        goto error;

So OBS makes a function call to the mbedtls library, requesting that the certificates in /etc/ssl/certs/ are loaded. Let’s make sure a proper certificate file is actually there where OBS expects it to be:

ca-bundle.crt is where it's supposed to be, but why is that file a different color?

Ca-bundle.crt is the file we’re looking for. Notice the teal color? Those three files are actually symlinks to another location. Files on Linux filesystems are symbolically linked all the time, so likely not a problem. I spent some time checking things like file permissions, and tried disabling selinux, but came up with nothing. It didn’t seem to be an overzealous security setting. All I was left with was the knowledge that I had an mbedtls function that should be loading the certificate bundle, but when the program actually tried to verify a TLS certificate, it complained that the chain, ca-bundle.crt, was missing. If the mbedtls function was failing, shouldn’t it error out there? The next logical step is to look at the documentation for that function.

Now we find the first real hint about what could be happening. mbedtls_x509_crt_parse_path() can partially fail, and still give us a return code that doesn’t trigger an error. So, time to use printf() to see what that return code is on my machine. I added the code, compiled, ran the output binary… and got no such log output.

It took longer than I care to admit for me to figure out why my code changes didn’t seem to make a difference when running the program. This is a potential gotcha to watch out for. OBS uses a modular structure, consisting of the OBS binary, as well as various loadable modules. The code changes I was making were a part of, and even when running the compiled binary, those modules were being loaded from their default locations. To test my changes, I had to explicitly tell OBS to use the newly compiled module.

System Calls That Hate Symlinks

Something was obviously amiss with mbedtls_x509_crt_parse_path(). I wasn’t seeing anything obvious in the documentation, but I did see a similar function, mbedtls_x509_crt_parse_file(). What would happen if we forced mbedtls to only try loading the one crt file that we care about? I made the change, compiled, and to my surprise OBS finally connected to Facebook Live. I had a real fix, but I still didn’t understand why it was broken. It’s time to look at the mbedtls sourcecode.

The parse_path() function is easily found in the mbedtls source tree. Make sure to watch the #if defined() blocks — We’re not interested in the code for Windows. Once we find the loop that runs for each file in the given path, the problem code might jump out at you.

        else if( stat( entry_name, &sb ) == -1 )
            ret = MBEDTLS_ERR_X509_FILE_IO_ERROR;
            goto cleanup;

        if( !S_ISREG( sb.st_mode ) )

Stat() is a system call that gets the status of a filesystem path, and then S_ISREG is a macro that checks whether that path is pointing at a regular file. Notably, the parse_file function does not do that check, and will happily load a symlink.

Report the Bug, But to Whom?

That, of course, is the core problem. Fedora uses a symlinked ca-bundle.crt, and mbedtls refuses to load ca-bundle.crt when it’s a symlink. We understand the problem, but what’s the proper fix? Which project actually has the bug here? OBS used the mbedtls function properly according to its documentation, and mbedtls may have a good security reason for refusing to load a bundle that’s actually a symlink. Is it on RPMFusion, and the package maintainer to fix the incompatibility? Personally, I think it’s really an mbedtls problem, particularly because this quirk isn’t mentioned in any documentation that I came across. Ultimately, it’s not my call which project needs to own this problem.

Our last task, then, is to report the bug we discovered. It’s a good idea to stop at this point, and ask yourself, is this bug a potential security issue? It’s best to try to report security issues privately, and most projects have contact instructions for disclosing those sorts of issues. Depending on where you found the problem, you may even be eligible for a bug bounty reward for finding the problem.

Assuming there is no security angle to consider, you’ll want to make a bug report. Does the project have a public bug tracker? That’s probably where it should go. If not, there is likely a mailing list where bugs are reported. Include enough information to reproduce the bug, and details on what you think is happening, but don’t include a bunch of log output in the bug or the mailing list. If it’s relevant, use pastebin or one of the other text hosting sites, to avoid including a wall of text in the bug report. If you have an idea of how to fix the problem, mention it. On a mailing list, patches are usually accepted. If the project is using Github or Gitlab, you can report the bug, and turn around and submit a pull request to fix it.

Particularly for trivial changes, I tend to ask what the project prefers, should I send a pull request, or is this trivial enough to fix without one. If you’re looking to do future work on the project, doing a PR is a handy way to get your name into the git record. Projects are more likely to look kindly on your future work, if there’s record of you already fixing bugs.

The End of Another Tale

This one turned out well enough. OBS is adding some workaround code to make sure the ca-bundle is properly loaded on systems where it’s a symlink. The mbedtls project sees this behavior as a bug, and I’ve submitted a patch to fix it. I noticed a related logic bug in the certificate loading code, and it’s been acknowledged as well. I’ve patched my copy of OBS so live-streams work again. It’s all in a days’ work for for the sysadmin. No rest for the weary, though. I have a pair of 10Gb Ethernet cards that die whenever they transfer VLAN tagged traffic. Just another case.


I know the more experienced programmers will point it out in the comments, stat() doesn’t ever set st_mode to S_IFLNK. Stat() follows the symlink to report on the target, while lstat() tells you about the symlink itself. My fix worked, but the problem was slightly different than I thought it was. Mbedtls_x509_crt_parse_path() can return a positive value if only some of the files in the specified directory successfully loaded. OBS was treating that positive value as a failure, and immediately dumping the certificates that had been loaded. Chasing false leads like this is totally par for the course when it comes to finding and fixing bugs. In the end, the bug is fixed, and that’s what really matters. Now if you’ll excuse me, I need to find something to wash the taste of crow out of my mouth.

Mon, 09 Jan 2023 10:01:00 -0600 Jonathan Bennett en-US text/html
922-098 exam dump and training guide direct download
Training Exams List