in-app purchase sandbox mystery: phone left in state unable to initiate purchase

I have an ad-hoc deployment of my iOS game, which includes in-app purchase. It is correctly set up with a purchasable item on itunes, and I have test users on itunes. I am able to successfully test it with my own iPod, and with a friend's iPod -- I can choose the item to purchase, get the price info correctly from the Apple server, choose to buy, enter the Apple ID and password for one of the test users, an the purchase completes successfully.

Another friend also installed the game on his iPhone and was starting to look at in-app purchase, but he followed an incorrect procedure, an now we can't get in-app purchase to work on his iPhone at all.

Specifically, he correctly signed himself out of the Store via the Settings application, then ran the game and chose the item to purchase. It correctly retrieved the price information. However, when the standard UI popped up and where he was supposed to click "Use an Existing Apple ID" he chose "Create a New Apple ID" by mistake. This brought him out of the game (game was sent to the background) and over to the web page to fill in the details for a new user. He realized that was wrong and returned to the game. But when he then tried to repeat he process, after retrieving the price info (again successfully), when he went to initiate the purchase, it errors out and never shows the standard UI where he can choose Existing Apple ID or Create New. So it's like his phone was left in a funny state. He tried rebooting the phone, reinstalling the app. Same problem. Then I recommended that he log in to the Store via the Settings app using his regular account, download a couple free apps, and then log out of the Store via the Settings app and try again. My thought was that this full开发者_如何学C process would somehow "clear out" whatever bad state his phone was in. But no dice. Same problem.

We can't figure out what state his device is in such that it fails when going to the purchase step of this sandbox in-app purchase process. I am still able to successfully complete the process on more than one other devices, so I don't think it's a problem with the state of the purchasable item or test users on itunes. It seems to be something specific to his device. I also had him using iPhone Config. Utility to watch the Console log as he went through this process. Very little was seen -- just an error code coming back after trying to initiate the purchase. (Nothing about PIPELINING errors and other web-service type errors that I've seen before when in-app purchase wasn't set up correctly on the sandbox.)

Any ideas on what state his phone could be in with respect to (sandbox) in-app purchase, and how we can clear it out?

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Reset your network settings (Settings -> General -> Reset -> Network Settings) Turn off your iPhone and turn it on again. Wait for 15 min (This is the time iOS caches AppStore credentials)

Try running the app again.