There is a new [well not so new anymore] fail safe when entering passwords and pins. If you mistype either - they will bunk you out of maple.
I would just be sure that you don't have caplocks on before begining to type. Also, you could have your password resent or reset via nexon.net. Just be sure you're still able to access the email address you used when signing up.
You can always just reset your pin as well.