APIException 10 on Google SignIn on Android

Question

I am trying to integrate Google Sign In/Authentication on my app. I have followed the instructions given in the firebase tutorial/guide and the following seems to work:

1. On UAT, which has a different firebase project.
2. The firebase app for production has the following keys' SHA1 listed on the Settings page:

• The internal signing key.
• The upload key
• The signing key on playstore.

My firebase google-services.json file has all the above three SHA1s listed.
The google developers console also seems to be setup correctly.

I still manage to get APIEXception 10 when I download the app through the 'internal app sharing' piece on the PlayStore. Everything works as expected even if I download the app from a Google Drive link.

Any help on this would be most welcome. I have scratched my head for a whole day now and tried out pretty much everything suggested on the internet on this issue.

Answer 1

Thanks to @Alex Mamo for his comment.

This answer was the key: https://stackoverflow.com/a/62763633/350685

To run firebase authentication successfully you need 4 (not 3) SHA-1 hashes associated with your firebase account:

1. Internal/debug key so you dont face any issues when running apps on your devices directly from Android Studio.
2. The key with which you sign the app for release.
3. The key that playstore uses to sign the app for release.
4. The internal app sharing key that you can find in the answer linked above.

Hashes for points 2 & 3 are available in the Settings section of the play store. No need to run any tasks on gradle for these.

I think this is not widely known because developers dont use the internal app sharing facility in large numbers yet (maybe?). Once this becomes popular, I am sure more will run into this.