Wont accept password!

I have three Apple devices, my MBP, my iPhone and an iPad. I am trying to download an App to my iPad but it just won't accept the password for my Apple ID account that I use on both the other two devices?
Any ideas folks?

Then go to https://appleid.apple.com/#!&page=signin and reset your password if you've forgotten it.

Yeh thanks! That's what I have now had to do on all three devices. All OK now.

Cheers