as the title suggests, just tried logging in to mp and got these 2 messages, it was working just fine a couple of hours ago.
i imagine i am not the 1st this is happening to so if someone can advise me on wt* to do i would be grateful.
cheers.

(p.s. already tried the "exit to single player then back again" routine but this doesn't work as it is remembering the code which is the correct one)

Did you download any DLC's lately?

It happened to me once a few weeks ago. I was kicked out of a match and a message popped up: "Code already in use"....but I don't have teh dlc, so it must mean the game-code....I did exit the game and startet it new, and it worked fine. I guess, if you're making a thread, just restarting the game didn't work out for you xD

sorted it, skipped the initial log in screen then logged in after pressing mp and that seemed to do the trick.