verification required to help ensure security of your Apple ID you must sign in and then verify your identity

When I try to purchase a movie on iTunes, I receive a message that says 'Verification required to help ensure security of your Apple ID, you must sign in and then verify your identity'

Then there is an 'okay' box to click, which I do and then I am back to where I started-trying to rent a movie!

I have repeatedly signed in and checked on all pertinent information in my account-to be sure of accuracy-and I also changed my apple id password to be safe.

I have tried signing out and signing back in, but to no avail.

HELP! This is really frustrating!