So I just re-installed Firefox and I started having this problem with some websites. (GoogleMail, Facebook, most https websites.) Here is the error: You have asked Firefox to connect securely to facebook.com, but we can't confirm that your connection is secure. Normally, when you try to connect securely, sites will present trusted identification to prove that you are going to the right place. However, this site's identity can't be verified. What Should I Do? If you usually connect to this site without problems, this error could mean that someone is trying to impersonate the site, and you shouldn't continue. facebook.com uses an invalid security certificate. The certificate is not trusted because no issuer chain was provided. (Error code: sec_error_unknown_issuer) --------------------------------------------------------------------------------- I have the same error for the other websites. I connected to them fine before the re-install. Please help. Thanks.