(Error code: sec_error_expired_issuer_certificate)
please follow the instructions in the Troubleshoot the "Secure Connection Failed" error message article. There you should be getting some information on what to do.
Thanks in advance, Tobbi, Firefox Support Volunteer
What is going on here? There are multiple posts about this error, and all of them show hundreds if not thousands of people who 'Have this problem too' and I have yet to see an answer that works for everyone. My Computer Clock is controlled by a group policy and is set to the exact correct time. I have modified my FF4 config to allow me to add bad certificates, but this didn't work either (as suggested in yet another forum). Why don't I have the ability to add a certificate as trusted for a site like gmail?
There should be no need to add an exception for a common site like Gmail (Google).
What kind of error do you get?
Did you retrieve the certificate and check that it is a Google certificate (Thawte SGC CA)?
If the data and time is correct then try to delete (or rename as a test) the file cert8.db in the Firefox Profile Folder.
Either your clock is wrong, your CA cert store is out-of-date or (scarily) someone's messing with your connection. Check them, in that order. I don't know if it's related to the DigiCert break-in, but it sure is scary.