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Server Not Found - Troubleshoot connection problems

If you have a problem connecting to a website, you may see error messages like Server Not Found. This article describes how to troubleshoot problems that cause this error.

Try another browser

To begin, try opening a website in another browser (such as Internet Explorer).

No browsers can load websites

If neither Waterfox nor your other browser can load websites, your problem is not in Waterfox so you should seek help elsewhere. Microsoft support includes these articles:

You should also check the following:

  • Make sure your modem and/or router are both on and are not indicating errors.
  • If you are using a wireless connection, make sure that you are connected to the right access point.
  • Make sure your Internet security software (including firewalls, antivirus programs, anti-spyware programs, and more) is not blocking connections to the Internet. For instructions on how to configure these programs, see the Configure firewalls so that Waterfox can access the Internet article.
  • If you use a proxy server, make sure that the proxy server can connect to the Internet. For instructions on configuring proxy settings in Waterfox, see Waterfox connection settings below.

Waterfox cannot load websites but other browsers can

If Waterfox cannot load websites, but your other browser can, follow the instructions below.

Cannot load websites after updating Waterfox

If you were able to load websites until you updated Waterfox, your Internet security software (including firewalls, antivirus programs, anti-spyware programs, and more) is likely preventing Waterfox from connecting to the Internet. Some Internet security programs can block Internet access even when they are in a “disabled” state.

In general, you should remove Waterfox from your program’s list of trusted or recognized programs, then add it back. For instructions on how to configure these programs, see the Configure firewalls so that Waterfox can access the Internet article.

Waterfox connection settings

If you connect to the Internet through a proxy server that is having connection problems, you will not be able to load websites. To check your connection settings in Waterfox:

  1. Click the menu button menu button and select Settings.
  2. Select the General panel.
  3. Scroll down to Network Settings and click Settings…
  4. Change your proxy settings:
    • If you don’t connect to the Internet through a proxy (or don’t know whether you connect through a proxy), select No Proxy.
    • If you connect to the Internet through a proxy, compare Waterfox’s settings to another browser’s (such as Internet Explorer - see Microsoft’s guide to proxy settings).
  5. Click OK to close the Connection Settings window.
  6. Close the about:preferences page. Any changes you’ve made will automatically be saved.

DNS Prefetching

DNS Prefetching is a technique Waterfox uses to speed up loading new websites. To disable DNS Prefetching:

Warning: Changing advanced preferences can affect Waterfox’s stability and security. This is recommended for advanced users only.

  1. Type about:config in the address bar and press Enter. A warning page may appear. Click Accept the Risk and Continue to go to the about:config page.
  2. In the Search field at the top of the page, enter network.dns.disablePrefetch.
  3. If the preference does not already exist, select Boolean and click the Add Fx71aboutconfig-AddButton button to create the preference.
  4. Change the preference value from false to true by pressing the Toggle Fx71aboutconfig-ToggleButton button.

IPv6

Waterfox supports IPv6 by default, which may cause connection problems on certain systems. To disable IPv6 in Waterfox:

Warning: Changing advanced preferences can affect Waterfox’s stability and security. This is recommended for advanced users only.

  1. Type about:config in the address bar and press Enter. A warning page may appear. Click Accept the Risk and Continue to go to the about:config page.
  2. In the Search field, enter network.dns.disableIPv6
  3. In the list of preferences, click the Toggle Fx71aboutconfig-ToggleButton button next to network.dns.disableIPv6 to change its value from false to true.

Waterfox cannot load certain websites

If you find that Waterfox can load some websites but not others, first clear your Waterfox cookies and cache:

  1. Click the menu button menu button to open the menu panel.
  2. Click History and select Clear Recent History…
  3. In the Time Range to clear: drop-down, select Everything.
  4. Below the drop-down menu, select both Cookies and Cache. Make sure other items you want to keep are not selected.
  5. Click OK.

Check for malware

If clearing your cookies and cache did not enable you to load the websites that did not work in Waterfox, you should check your computer for malware. Certain types of malware are known to target Waterfox and can prevent it from loading various websites:

  • If you have an antivirus or Internet security program, update its detections database and do a full scan of your system.
  • If you still have problems, see How do I get rid of malware?.

Based on information from Error loading websites (mozillaZine KB)