I got this several times while trying to log in this morning.
Me too, just before 3am UK. Strangely only on one account. Other accounts loaded and played fine but, when I backed out to the account login screen, the error was there.
Since last night I have the same problem, but only for 1 of my 3 accounts. With the other 2 I had no problem to login. Between the last correct login on Saturday and the first failure on Sunday with that 3rd account, I have not changed a thing. Any thoughts on that ?
Thank you for the update regarding the login error. With the error resolving itself after a few login attempts, we've decided to now close the thread from further discussion.