I have a credit card that I use to make online purchases. I used it on my iTunes account as well.
Now, however, I have bought a new machine and iTunes complains, "You are logging in from a new machine. You must verify your payment information." I am moved to the payment information and prompted to enter my security code. iTunes won't accept it. I have double-checked and everything, but I keep being returned to the payment information page. The page prompts, "Please enter valid Security Code."
The code I enter is valid (I know where to find it and have used it before). I see other reports of this on the internet, but no solution. Is there a known workaround to this?
Disclaimer: iTunes is not a web app, but the store inside of it is.