I've had this problem happen at work. The error sticks around for about 1/2 of the day, but then poof -- I'm able to log in without an issue.

I've never been able to determine the reason for the error. It never happens at home, I've always assumed it had something to do with the servers at work, even though it never made a ton of sense since it always eventually just starts to 'magically' work.

I had no idea there were people experiencing it as a permanent error though. That would be frustrating.