Error messages: what they mean and how to fix
How to troubleshoot error messages on Firefox
- How to troubleshoot "Your connection is not secure" error codes on secure websites Learn about the error codes SEC_ERROR_UNKNOWN_ISSUER MOZILLA_PKIX_ERROR_MITM_DETECTED and ERROR_SELF_SIGNED_CERT on HTTPS websites and how to troubleshoot.
- How to troubleshoot time related errors on secure websites This article explains why you might see time-related errors on HTTPS websites and how you can troubleshoot them by correcting your system clock.
- Troubleshoot the "Secure Connection Failed" error message If Firefox can't access a secure (https) site you'll get a "Secure Connection Failed" page. Learn the reasons this happens and what to do.
- "Firefox is already running but is not responding" error message - How to fix it How to start Firefox if you see an error message, "Firefox is already running, but is not responding" or, on Mac OS X, "A copy of Firefox is already open".
- Certificate Pinning Reports Firefox certificate pinning reports; what they are and why you might want to share yours.
- How to fix the Update Failed error message when updating Firefox This article presents solutions and workarounds to a failed Firefox update so that you can get it updated and working correctly again.
- Warning Unresponsive script - What it means and how to fix it This article describes the reasons for this error message and covers possible solutions and workarounds.
- Firefox says it's just updated every time it starts - how to fix If you see "Firefox Updated" or "You've been updated to the latest version of Firefox" every time you start Firefox, we'll show you how to fix it.
- Fix "The bookmarks and history system will not be functional" error message This article explains what to do if you see the error message "The bookmarks and history system will not be functional" when you start Firefox.
- Warning Unresponsive plugin - What it means and how to fix it This article describes the reasons for this error message and covers possible solutions and workarounds.
- What do the SSLv3 error messages mean on Firefox? When accessing a site with SSLv3, Firefox will block it and display an "Unable to connect securely" message.
- File system paths on Linux are always treated as UTF-8 On Linux, the profile path is required to be valid UTF-8. Names of downloaded files are encoded in UTF-8 regardless of glibc and glib settings.
- What does "Your connection is not secure" mean? When connecting to a website that uses an invalid certificate or weak encryption, Firefox will display a "Your connection is not secure" error page.
- How to run Firefox when your profile is missing or inaccessible How to fix the error ''Your Firefox profile cannot be loaded. It may be missing or inaccessible'' so that you can start and run Firefox.