Apple GameCenter authentication: works on Tesflight but not during app review

Hi,

I am currently developing a game with Unity 2017 (2.0f3). This app targets iOS only and it uses in-app purchase, so I need to make sure the player is connected to Game Center when playing.

• The game works perfectly on my device, I test it with Tesflight external tests.

• But the connection to Game Center fails on the App Review side, so my game is rejected by Apple.

What could be the difference between my environment and the Apple team environment?

I posted the same question on the Apple Developer forum, but I also post here because I wonder if the issue is related to Unity implementation.

Here are some informations:

• The failure is due to a time out: the authentication request doesn't return on Apple side.

• I have already succeeded to upload another app on the App Store. This app was developed in the exact same conditions and used a custom login rather than the Game Center.

• My game doesn't use any leaderboard or achievement, just the in-app purchase, so I haven't configure any leaderboard or achievements.

• I am new with Game Center but I am an experienced Unity developer so I am absolutly sure the problem is a time out with the authentication request and doesn't come from another part of the code.

Any idea about the issue?

Does someone have an experience of GameCenter and in-app purchase with Unity?

Please let me know if you need additional information or resources like code parts.

Any help would be greatly appreciated.