Firebase flutter app was released on Google PlayStore. But fatal issue occurred with google sign in

Question

I recently successfully published my first flutter app connected to firebase with firebase-googleSignInAuth. I tested it several times by building apk with command line. In this case, googleSignIn just worked fine. But when I downloaded my own app from playStore after well reviewed by google, following problem occurred:

I clicked a button calling googleSignIn(connected to firebase) function, then google pop-up came up. I entered my google account which is already listed on my firebase db, and the logIn process just worked fine with the pop-up screens. At this point, the problem occurred: I entered correct google account info and the pop-up from google was gone. But NOTHING happened and the logIn screen was there again. Several more same trials with restarting, re-downloading, but all didn't worked at all.. In my code, if the auth function called user info properly, home screen comes, otherwise the logIn screen comes, which means that the googleSignIn didn't work well. So I built apk from same codebase of the aab(appbundle file) uploaded to playStore, then tested it in various android devices. Unfortunately, they all worked okay with that googleSignIn issue. It seem like the problem must be in process that publishing the appBundle to playStore.

Does anyone know how to solve this playStore problem? I'm new to publishing apps so cannot find out proper solution for this issue and so devastated after all.

Of course, flutter doctor said no issue found ]:

Clear answers so appreciated! Thank you in advance! [:

Answer 1

I think the problem you have is in adding a SHA-1 certificate fingerprint to the uploaded application. You can add it in the Firebase project.

First: Go to Google Play Console > Release Management > App Signing > Copy SHA-1 certificate fingerprint.

Second: Go to the Firebase project > Settings > Add fingerprint.

After applying these steps, you can try the application without re-updating the .abb version.

SHA-1 is defined as: It is a standard for the implementation of a 'secure hash algorithm' - a one-way cryptographic function that can be used to act as a 'signature' of a sequence of bytes. It is very unlikely that 2 different byte sequences would produce the same value (though not impossible).

You can read more with Documentation.