Having Log-in problems is common. So don't worry. Well first of all, the log in is Capital Sensative. So make sure CAPS lock is off, and all the right letters are capitalized(if any). If you've checked that, there is a few other things to make sure of. Basic things to check like Internet Connection. Also a common issue is if your username is more then 16 characters. It works on the forums but the game has a 16 character limit. If that's the case the only known solution is to wait and make another account with a shorter username.