if you haven't been there before you'll need to register with the same e-mail address you used during checkout.
once you get in, if you have any active sessions you can kill them so you can login. but by the time you get registered i suspect you should be able to login anyway. since sometimes the server will hold onto your session for a little while after you close out the bot. once the server lets go, or you kill the session you should be able to log in again.