Android Firebase Auth signInWithCustomToken fails only in production app

[coolcool1994]

I am using: implementation 'com.google.firebase:firebase-auth-ktx:19.3.2'

I have a production app, and signInWithCustomToken is failing every single time. Task here is always unsuccessful in the production app. Firebase.auth.signInWithCustomToken(custom_token).addOnCompleteListener(activity){ task ->

I was so alarmed so I just ran the app from Android Studio in debug build, and signInWithCustomToken is successful every time.

I reinstall the production, and signInWithCustomToken fails every time.

Why does Firebase.auth.signInWithCustomToken fail in the production app every time when the debug app from Android Studio is successful every time? In iOS, everything works in both production and in debug. Just in Android it's the problem. And In production, it used to work before a few days ago (the same app). I attach logcat of the release build (production) app

2020-10-01 22:27:47.910 2450-2475/? E/FirebaseInstanceId: Failed to get FIS auth token
    java.util.concurrent.ExecutionException: com.google.firebase.installations.FirebaseInstallationsException
        at com.google.android.gms.tasks.Tasks.zzb(Unknown Source:61)
        at com.google.android.gms.tasks.Tasks.await(Unknown Source:23)
        at com.google.firebase.iid.GmsRpc.setDefaultAttributesToBundle(com.google.firebase:firebase-iid@@20.2.3:55)
        at com.google.firebase.iid.GmsRpc.startRpc(com.google.firebase:firebase-iid@@20.2.3:37)
        at com.google.firebase.iid.GmsRpc.getToken(com.google.firebase:firebase-iid@@20.2.3:13)
        at com.google.firebase.iid.FirebaseInstanceId.lambda$getInstanceId$2$FirebaseInstanceId(com.google.firebase:firebase-iid@@20.2.3:164)
        at com.google.firebase.iid.FirebaseInstanceId$$Lambda$4.start(Unknown Source:8)
        at com.google.firebase.iid.RequestDeduplicator.getOrStartGetTokenRequest(com.google.firebase:firebase-iid@@20.2.3:14)
        at com.google.firebase.iid.FirebaseInstanceId.lambda$getInstanceId$3$FirebaseInstanceId(com.google.firebase:firebase-iid@@20.2.3:163)
        at com.google.firebase.iid.FirebaseInstanceId$$Lambda$1.then(Unknown Source:6)
        at com.google.android.gms.tasks.zzf.run(Unknown Source:2)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
        at com.google.android.gms.common.util.concurrent.zza.run(Unknown Source:6)
        at java.lang.Thread.run(Thread.java:919)
     Caused by: com.google.firebase.installations.FirebaseInstallationsException
        at com.google.firebase.installations.FirebaseInstallations.doNetworkCallIfNecessary(FirebaseInstallations.java:382)
        at com.google.firebase.installations.FirebaseInstallations.lambda$doRegistrationOrRefresh$2(FirebaseInstallations.java:350)
        at com.google.firebase.installations.FirebaseInstallations$$Lambda$4.run(Unknown Source:4)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
        at java.lang.Thread.run(Thread.java:919) 
2020-10-01 22:27:47.958 2450-2509/? E/Firebase-Installations: Firebase Installations can not communicate with Firebase server APIs due to invalid configuration. Please update your Firebase initialization process and set valid Firebase options (API key, Project ID, Application ID) when initializing Firebase.
2020-10-01 22:27:47.975 2450-2478/? E/FirebaseInstanceId: Topic sync or token retrieval failed on hard failure exceptions: FIS_AUTH_ERROR. Won't retry the operation.```

[google-oss-bot]

I couldn't figure out how to label this issue, so I've labeled it for a human to triage. Hang tight.

[coolcool1994]

I solved this by not restricting API Key. In the Google Cloud Platform Console - > Credentials - > Android key (auto created by Firebase) -> set "Application restrictions" from Android to None.

I want to set this to be Android for security reasons, but if I set it to Android only (which only my android app is using), I the the error (posted above) only in production. This is very strange because this error only occurs my app in production, but in debug app that I run from Android Studio.

[coolcool1994]

SOLVED:

I had to add release/production SHA Fingerprint as well as debug! I only had the debug SHA Fingerprint, and it turns out release has a different SHA Fingerprint. Release SHA Fingerprint can be found in the GooglePlay Developer Console under App Signing which is under Release Management

[rlazo]

Hi @coolcool1994 thanks for documenting your process to find what was wrong and fixing the issue! It will be useful for reference for anybody seen a similar issue in the future.

Since it's solved now I'll close it.