Try resetting the PW. Also, are you sure that you are using the right ID?

Is there a way to find my Apple ID Name if I can't remember it?

Yes. Visit My Apple ID and click Find your Apple ID. See Finding your Apple ID if you'd like more information.

How do I change or recover a forgotten Apple ID Password?

If you've forgotten your Apple ID Password or want to change it, go to My Apple ID and follow the instructions. See Changing your Apple ID password if you'd like more information.