Did you activate your account through your email?
I looked into this a little bit, and it looks like your username is over 16 characters. Users who have a username over 16 characters are not able to log into the game. Unfortunately, you can't change your username, so signing up for a new account when the Registration is open is the only solution. The Registration can be sneaky, but I'm sure you'll catch it in no time! c:
Also, if your user is over 16 character as explained above by Nynx, you won't be able to log in.
I hope this helps.~