Invalid joinkey: Unable to decrypt the join key -- most likely it was encrypted for another server. If you're on the development server, you've probably logged into the wrong account in the development server. Actual Error Message: Padding is invalid and cannot be removed.
Played for few hours, left browser with game open. Few hour later I'm back at my computer and after clicking "back" in lobby, and than "Play Online" i get this error. My IP changed, as it does every 24h with reconnecting, but that didn't seem to be a problem before (it did change few times in past while game was open and nothing happend except from kicking me back to lobby).