Google sign in doesnt work on production

I know this is an old question, but for anyone using Firebase, you have to add the SHA-1 fingerprint to the Firebase Console > Settings > Android App page.

If you are using the Google Play Console, you can get this from the Google Play Console > App Signing page. There will be two of them (the one you signed your app with, and the one that Google signed your app with). You'll need to add both so you can test local release builds.

If you don't use the Play Store, you'll need to get the SHA-1 fingerprint from your keystore file using these directions: https://developers.google.com/android/guides/client-auth

You need to have a configuration file with,

Android Signing Certificate SHA-1 with release key so only it will work with release build