Android Firebaseui Sign In With Google Error For Release Key

I'm getting the the Developer (Code:10, message:10:) error when trying to sign in using Google Sign-in while using FirebaseUI's Authentication. All works well on development, but w

Solution 1:

So... It turns out that there are 4 (FOUR) signing keys that might be needed... The fourth one is for internal app sharing (which I was using) via Google Play. To find this key, you need to navigate to Google Play console as shown below:

Add that key to your Firebase console settings, download the new google-services.json into your project and run.