Q: imessage Problem

My imessage on my Macbook Pro has been working fine until last night. I used it, then closed my laptop and two hours later I opened my laptop to use it again and I had been logged out. When I went to log back in, I entered the correct password and it started processing my request but I got a message that said "The server encountered an error processing registration. Please try again later." It won't let me sign in and I don't know why. I have not updated to Mavericks but I don't think that should be the cause of the problem. My Macbook Pro is only about a year old.

Does anyone know what's wrong? Does anyone know what I can do to fix it? Or do I have to update to Mavericks?