Are you getting an untrusted connection warning in Mozilla Firefox? It’s actually an error message reflected by Firefox when it finds a connection untrusted. In such a situation, you can’t log into that particular website that is reflecting the error. This problem may arise due to the invalid certificate support which again, may occur due to one of the following reasons:

  • Certificate of the error-giving site will not be valid until the server’s or your computer’s date.
  • The site reflecting the warning uses an invalid security certificate.

See this Firefox Support article for more information on this error message.

Generally, users experience this error when their computer’s system clock is not working correctly. In such a case, the problem can be fixed by correcting the system date.

Note: If correcting computer’s date and time from the OS system options is not working, you need to replace the BIOS or CMOS battery of your computer with a new one. This will fix the problem immediately.