Hi, I understand that you are receiving an error when you try to connect to en.wikipedia.org and have already tried to change the default fallback. Please update your plugins to the latest version. Check to make sure you are up to date: *[https://www.mozilla.org/en-US/plugincheck/] If you see any issues also see: *[[Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems]] Second, please make sure to check the message on the security certificate found int he page info [[Page Info window - View technical details about the page you are on]] Please also see: [["This Connection is Untrusted" error message appears - What to do]]