The registering device does not have appropriate credentials?

The FaceTime on my Mac wasn't working last night, when i tried making a call, the calls would always fail. I updated my system, restarted my computer, logged out of FaceTime but when I tried logging back in, it would take me to a verification page, and then say that the servers could not process my request. I changed my password on my Apple ID and verified a new e-mail, but still nothing. I left it alone for a while, now this morning, when I tried signing back in, I have the same problem, but instead it said "The registering device does not have appropriate credentials" I've had this Mac for almost a year with no problems and I've always used FaceTime without a problem. I have version 10.7.5