Firebase Auth: Requests from this Android client application com.xxx are blocked

Question

I\'m implementing the standard tutorial for Firebase AuthUI in my android app. However, when testing I try to sign-in using Google sign-in from within the app and get the follow

Answer 1

For anyone else who might be facing this problem, it is possible that you are using Internal App Sharing on the Play console, with Google signing enabled. If so, you may have forgotten to add their debug SHA-1 key to your firebase console.

Pretty hard to debug, or find an answer, so I'm hoping I've added all the right keywords to help the next guy.