Can't log into iMessage app

[RichardC300]

I was hoping 10.8.3 would fix this, but it's been happening since December. I've tried everything from deleting all related entries in Keychain to completely redoing the hosts file. I've googled for a solution and a mention of a missing serial number came up, but mine is not missing. Has anybody encountered a fix to this problem?

 

[nyolc8]

This problem was on hackintoshes... Do you using an actual Mac, or a PC with OSX installed?

If you using a Mac, did you bought it in new condition or in used, maybe refurbished? I asking this because on some used or refurbished machines the serialnumber got deleted, and that is confuse the imessage service and it won't allow to log in.

 

[RichardC300]

I'm using an early-2011 15" MBP that I bought new. I've never taken it in for repair or anything like that. I feel like this problem appeared out of nowhere in December, and I don't think it was related to the 10.8.2 update, because it was released in November.