I can't log on with my Alt, I'm getting the same message as if I'd tried to do it with my main account if it was already logged on. Are we now checking for logins by IP rather than MC Account?
dont worry, i used to ge tthe messeage all the time,its just a bug, refresh the server s list a couple times then try again , it worked for me
Sometimes the session entry doesn't get removed and connecting to the last server you was on fixes it, but I now have it automatically removing old session too every 15 minutes