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).
- If all other browsers cannot load the website, move on to the No browsers can load websites.
- If the other browsers can load the website, skip ahead to the Firefox cannot load websites but other browsers can section.
No browsers can load websites
If neither Firefox nor your other browser can load websites, your problem is not in Firefox, so you should seek help elsewhere
, for example, at Microsoft.com:
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.
- If you use a proxy server, make surethat the proxy server can
connect to the Internet. For instructions on configuring proxy settings
in Firefox, see Firefox connection settings below.
Firefox cannot load websites but other browsers can
If Firefox cannot load websites, but your other browser can, follow the instructions below.
Cannot load websites after updating Firefox
If you were able to load websites until you updated Firefox, your
Internet security software (including firewalls, antivirus programs,
anti-spyware programs, and more) is likely preventing Firefox 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 Firefox from your program's list of
trusted or recognized programs, then add it back. For instructions on
how to configure these programs.
Firefox 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 Firefox proxy settings:
-
Click the menu button
and choose
Options.
- Select the panel.
- Select the Network tab.
- In the Connection section, click Settings....
- 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 Firefox's settings to another browser's (such as Internet Explorer - see Microsoft's guide to proxy settings).
- Click OK to close the Connection Settings window.
-
Close the about:preferences page. Any changes you've made will automatically be saved.
DNS Prefetching
DNS Prefetching is a technique Firefox uses to speed up loading new websites. To disable DNS Prefetching:
- In the Location bar, type about:config and press Enter.
- The about:config "This might void your warranty!" warning page may appear. Click I'll be careful, I promise! to continue to the about:config page.
- Right-click
in the list of preferences, select , and then select .
- In the Enter the preference name window, enter network.dns.disablePrefetch and click OK.
- Select true when prompted to set the value and click OK.
IPv6
Firefox supports IPv6 by default, which may cause connection problems on certain systems.
To disable IPv6 in Firefox:
- In the Location bar, type about:config and press Enter.
- The about:config "This might void your warranty!" warning page may appear. Click I'll be careful, I promise! to continue to the about:config page.
- In the Search field, type network.dns.disableIPv6
- In the list of preferences, double-click network.dns.disableIPv6 to change its value from false to true.
Firefox cannot load certain websites
If you find that Firefox can load some websites but not others,
first clear your Firefox cookies and cache:
- Click the menu button
, choose History and select .
- In the Time Range to clear: drop-down, select Everything.
- Click the arrow next to Details to display the list of items that can be cleared.
- Select both Cookies and Cache.
- Click Clear Now.
Check for malware
If clearing your cookies and cache did not enable you to load the
websites that did not work in Firefox, you should check your computer
for
malware. Certain types of malware are known to target Firefox 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.
