Our App has an in-app purchase (IAP) which works correctly using sandbox tester accounts. Our App was rejected with the following message:
"We found that your in-app purchase products exhibited one or more bugs when reviewed on iPad running iOS 11.3.1 on Wi-Fi connected to an IPv6 network.
Specifically, we are unable to buy the IAP due to the buttons not responding to touch."
Our best guess is that Apple reviewers are getting an invalid product ID and that is why the buttons don't respond. We believe this is so because when we change the product ID inside our app we get the same behavior where the IAP buttons don't do anything (will now set an alert). Anybody else encountered this issue before. We have tried our app with many different scenarios and sandbox tester accounts and IAPs are working correctly.