Fix problems connecting to websites after updating Firefox
This article describes how to troubleshoot problems connecting to websites that start immediately after updating Firefox to a new version.
Follow the instructions in this article if you can connect to websites using another browser (such as Internet ExplorerSafariEpiphany), but not in Firefox. If no browsers can load websites, see Firefox and other browsers can't load websites.
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.
This problem occurs when your Internet security program was set to trust the previous version of Firefox, but no longer recognizes your updated version as trusted.
Note: In some cases, disabling an Internet security program or firewall does not stop all of its parts from being active. A program that reports that it is disabled may still be able to block Firefox.
Fixing the problem
To allow Firefox to connect to the Internet again:
Make sure your Internet security software is up-to-date (i.e. you are running the latest version).