Problem with testing In App with sandbox test account

I created a test user account through the Manage User Accounts in iTunes Connect. When you create such an account you have to select a valid storefront for your account. I chose US Store. Now I signed out from the store in App Store settings on my device. Ran the application and tried to perform a purchase. I successfully login with my test account. After I press Confirm when entering my credentials I get an alert, that comes from SKPaymentTransactionStateFailed from the observer. It says "Your account is only valid for purchases in the US iTunes Store". The error state = 0 unknown. Second time when i try to perform the purchase, StoreKit only asks me for a password like the previous login was successful. After entering a password I can perform a purchase. My开发者_如何学Python question is whether it's only because it's a testing account and the application is not actually on AppStore? What should I do to avoid this message or at least to continue the purchasing process?

Thanks a lot,

Nava

Well, i found a nice blog with a code library that allows to add an In-App Purchase to your free application. In the end the guy answers the question I've asked him there:

http://blog.mugunthkumar.com/coding/iphone-tutorial-–-in-app-purchases/

Shortly the behavior I'm experiencing is not a bug, it's a feature and iTunes also works this way. When you're sign out and sign in again, it says, that your purchases are valid only in the store you have account in and it takes you to that store.