Hey guys, just went through this exact situation with our upcoming India softlaunch. Thought it was odd, considering our project is Blueprint-only.
So I followed IPv6 test instructions provided here:
by Apple. If you scroll down a bit, you’ll see a “Test for IPv6 DNS64/NAT64 Compatibility Regularly” section. To my surprise, our game’s In-App Purchases worked just fine. Airplane mode on, all other networks forgotten, only connected to the test IPv6 network, with visible IPv6 address in the network settings.
So I resubmitted with a very detailed description in the Review Notes section about how I tested and confirmed functionality per their own instructions. I also added a “Waiting for In-App Purchase Response” window in our game whenever an IAP command is sent, because I realized that if it takes a bit to respond and the presses it again, it sends back a failure result in UE4. I let them know in the Review Notes about this addition and why I think they previously saw the error.
They just approved it for release after they reviewed that submission. I had also prepared a video of myself setting up the test and successfully running, just in case they rejected it again.
Hope this helps. I certainly understand the frustration and confusion.