@Chesire, the information you have posted was already shared, I know you were trying to help but the user above you already posted the same thing, keep an eye out next time ey? ^^
As of above states, do not log in with your forum display name, use your username, like my forum name is Whisperingwaves But I wouldnt log in as that, I would have to use my username HidenShadow If that dosn't work make sure your username/password is not longer then 16 characters long and be sure your caps lock is off, if your username/password is longer then 16 charcacters long then it will not work, which means, you would need a new account.
Hope this helps floof.
~Whisper <3