Some problems I can think of:
- Does your password have numbers? if so, don't use the numpad to type the password. Use the number row (above the letters).
- Check you didn't hit the CAPs lock
- Your username and password should be the same as the one you use on the login page.
- Some symbols don't work right on the game, maybe try using a password without symbols if you have them.
- If you have an automatic password typer, it usually types too fast for the game to pick up the keys correctly.
