Unity Android app will no longer log into Google Play

Question

I have seen several threads around this issue but I am still struggling. My app is failing to sign in on Android with:

Unexpected response code 403 for https://www.googleapis.com/games/v1/players/me?language=en_US

I had this all working about 4 months ago but my hard drive failed and I am trying to get things working again on a newer version of Unity. I am only having this problem with NEW builds. My old apk still works fine so everything must be fine in the Google Play Developer Console. Something is not setup right in Unity.

I have tried with and without setting the "OAuth2 Client ID" from the Developer Console in the Android settings.

I have tried setting the keystore to .android/debug.keystore using the androiddebugkey with "android" as the password for both.

What else could it be?

Answer 1

So to sum up my comments up in an answer, that might be useful to somebody else.

1.) An app authenticates itself towards the Google Play Services with the combination of Keystore and Package name.

You can't sign in without or with another keystore. So you should always backup the keystore file together with your project in a version control system, that is safe from a single hard drive failure.

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2.) If you lose keystore file, you can not update your app anymore.

But you could create a new app and link it to the same Google Play Game.