It seems I get this issue only when trying to make a new character. I am still able to log into my main and my alts but for some reason, when I go to make a completely new character it boots me and tells me that I have to register the game. I checked out the Mogstation too, and yep, everything is registered. I have no advice, Im just letting you know you're not alone in this and hopefully some one will see this who does know what to do.