According to Playonline the server for registration was having some technical issues. Which were down for about two hours during the late morning or early afternoon. From what it sounds like the problem has been fixed. So you should be able to return without any problems. Depending on what part of the world you fall in late morning or early afternoon could be different times but it looks to have been fixed 6-7 hours ago. If you're still having problems then I'm not sure, maybe completely logging out and shutting down.