The first thing that comes to mind is the api key declared in the manifest

<meta-data
            android:name="io.fabric.ApiKey"
            android:value="..my api key.." />

I remember having errors with my build until I remembered to remove that from my manifest

If that’s not the issue I would double check the dependencies match whatever the most up-to-date migration instructions are in the Firebase console. Perhaps something is still using the old sdk

Beyond that, I’m out of ideas off the top of my head.

Let me know if that helps. If not, we can brainstorm some more.