iMessage Authentication not working

Hey, I just got this MacBook Pro for Christmas and never had an iPhone or any apple stuff before. I set up my iCloud account already but when I try to use iMessage it says "Error while Authentication". I have already restarted my Mac, made sure the wifi is working, and even deleted and reentered my iCloud account onto the Mac. Deleting and redoing only worked for a couple of seconds before it kicked me out and went back to the error. Please help.