Login loop while buying an app
I'm trying to buy an app on my iPad, and I'm getting stuck in an infinite login loop.
What happens is:
I go to buy the app (in this case it's Air Display), I hit the "buy app" button,
I sign in (as the usual protocol)
It goes to the home screen, and then a popup says "Verification Required: Before you can make purchases, you must tap Continue to sign in, then verify your payment info."
I hit "continue," a small box appears, and prompts me to log in AGAIN, I hit OK, and the login box keeps re-appearing asking me to log in.
So what's up with this? This is obnoxious. I verified my payment info on my mac on the iTunes account info page so I know that's out of the way.