I implemented sign-in with apple on my ios application and it's been working perfectly on my end, whether it was run on a simulator or a real device or with the latest ios version (13.5). It also worked perfectly during internal beta-testing when I released it on TestFlight.
However, upon submission of my app to Apple, it was rejected for incompleteness by a quite contradictory error. When they attempted to sign in after choosing to hide or show email, an alert generated by the Sign-In with Apple system was presented stating that they were not connected to wifi, even though from their screenshot it would appear that they were.
I tried to reproduce the error in as many ways as possible on my end, using different combinations of wifi, VPN, and cellular. The ONLY way I was able to generate the "Could Not Connect" error was by actually not being connected to wifi or cellular.
If I had ever come across this error on my end, I would've dismissed as some connection confirmation error tried to sign in again, which I would assume to work the second time (if the error itself really was an error of some sort). However, this happened only on Apple's end, and when I asked the reviewer to attempt the sign-in one more time, making absolutely sure that they were properly connected to wifi, I did not receive a response.
My question is that is this an actual issue that occurs with Sign-In with Apple, and if so what would the solution be, or is this just a one-time glitch on Apple's end, which in that case I should just re-submit my app and hope that it doesn't occur again?
This is the screenshot of the error they got:
