Google Play Games Services working on Emulator but not on real device

Hey Guys,
i implemented plugin.gpgs.v2 in my project code and did all the requirements from Google Play Console and Google Play Cloud to make it work.
I tested it on Memu and its working there but when the APK is installed on a real Phone, we dont get the login screen anymore… i dont get why its working on an emulator but not on a normal device…

I did some troubleshooting and i have the right AppID, the right package name and also the right SHA1 fingerprint confirmed.

Im located in Germany and the app is set to default english. Is there maybe a region lock? The Emulator could be located in USA.
But i also changed my ip via VPN and it wasnt working…

EDIT:

I figured out, that if i transfer the apk directly to my phone, its working but when i install it via Google Play, its not working.
Has anyone an why its like that?

EDIT v2:

Its working now.
The error was, that the fingerprint i put in Google Could OAuth wasnt the same frome the final apk from the Play Store.
I dont know why the local builded apk and the Play Store apk have different fingerprints, but when i put the fingerprint from the play store apk as OAuth ID, its working.
Maybe this will help someone else in the future.