No proxy web Browser
This article describes problems where Firefox cannot load websites, but other web browsers (such as Internet ExplorerSafariEpiphany on Gnome or Konqueror on KDE) can. When this happens, Firefox may show a Server not found or Unable to connect error message.
If you were able to load websites until you updated Firefox or until your Internet security software was updated, reconfigured or a new one was added, your Internet security software (including firewalls, antivirus programs, anti-spyware programs, and more) is likely preventing Firefox from connecting to the Internet.
Note: Some Internet security programs can block Internet access even when they are in a "disabled" state.
In general, you should make sure your Internet security software is up-to-date and remove Firefox from your program's list of trusted or recognized programs, then add it back. For instructions on how to configure some programs, see the Configure firewalls so that Firefox can access the Internet article.
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.Preferences.
- Select the panel.
- Select the Network tab.
- In the Connection section, click Settings….
- Change your proxy settings:
- Close the Connection Settings window.
- Close the about:preferences page. Any changes you've made will automatically be saved.
In the address bar, type about:config and press EnterReturn.
- The about:config "This might void your warranty!" warning page may appear. Click I'll be careful, I promise!I accept the risk! to continue to the about:config page.
- In the FilterSearch field, type network.dns.disableIPv6.
- In the list of preferences, double-click network.dns.disableIPv6 to set its value to true.
- Right-clickHold down the Ctrl key while you 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.
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.