I have noticed that there are some recurring issues with a common solution so I thought I would list some here for you to try for a quick fix.
Login Problems: Forums vs Game
Solution 1: First make sure you have the correct login - the forum and game use different logins (this can be an issue if you use any type of password software - it can input the wrong ID & password). Also your Game ID is your email address, it is not your character name. Your Forum ID can be anything you input (I would suggest using your character/avatar name - this way friends will recognize your posts and also game prizes from the forum will be sent to the correct account without issue.)
Solution 2: Request a new password - this is done by pressing the Forgot your Password? link on the login badge. You will see a message that the token has been sent. This will send an email to your listed email address that you can use to reset your password. You then need to login using the new password. If you use Password Software to store passwords - make sure it updates the new password.