Nostalrius Begins - Quality wow vanilla realm (1.12)

I tried to log into Nostalrius Begins this morning when my username field was empty. I tried to enter it but my username was too long for the bar and thus was unable to log in. This has never been a problem before and ive been playing for almost a month now. I would appreciate any and all help in this Matter

Are you sure? I seem to remember the username field strictly limiting up to 16 characters in length.