firebase-android-sdk: Various exceptions in signInAnonymously()

[REQUIRED] Step 2: Describe your environment

• Android Studio version: 3.5.1
• Firebase Component: Auth
• Component version: 19.1.0

[REQUIRED] Step 3: Describe the problem

Steps to reproduce:

I authenticate users anonymously with signInAnonymously() and added a log of exceptions to my server from addOnFailureListener() after many reports that something isn’t working. I got 5 kinds of exceptions, none of which I could not find how to fix. It looks like a bug. Here are they:

• com.google.firebase.FirebaseException: An internal error has occurred. [ 7: ]
• com.google.firebase.FirebaseApiNotAvailableException: Error resolution was canceled by the user, original error message: CANCELED: null
• com.google.firebase.FirebaseApiNotAvailableException: API: InternalFirebaseAuth.FIREBASE_AUTH_API is not available on this device. Connection failed with: c{statusCode=SERVICE_INVALID, resolution=null, message=null}
• com.google.android.gms.common.api.ApiException: 8: The connection to Google Play services was lost
• com.google.firebase.g: A network error (such as timeout, interrupted connection or unreachable host) has occurred.

First is the most popular. The latter is not necessarily a bug, but I do not know how they were able to send a log to the server if they do not have Internet.

Relevant Code:

FirebaseAuth.getInstance().signInAnonymously()
                    .addOnCompleteListener(new OnCompleteListener<AuthResult>() {
                        @Override
                        public void onComplete(@NonNull Task<AuthResult> task) {
                            if (task.isSuccessful()) {
                                FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();

                               // ...
                            }
                        }
                    })
                    .addOnFailureListener(new OnFailureListener() {
                        @Override
                        public void onFailure(@NonNull Exception e) {
                            // log exception to server