"You have asked Firefox to connect securely to forum.knotty.me, 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. 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."

And then it also says that: "forum.knotty.me uses an invalid security certificate. The certificate expired on 8/8/2015 5:35 PM. The current time is 8/9/2015 5:56 PM. (Error code: sec_error_expired_certificate)"

Is it safe to connect at this point due to an expired certificate or is this for real?