always seeing “sign in required to enable touch id” prompt after making successful purchase

[ajonno]

when we complete a successful purchase, every single time this prompt displays. why is that?

[jeffie]

It seems a bug for iOS11,you can try like this, This is what worked for me: https://stackoverflow.com/questions/46257633/ios-11-is-in-app-purchase-testing-using-a-sandbox-user-keeps-asking-to-sign-in