Firebase Authentication - Initializing Multiple Projects (firebaseuiexception: Code 10)

Expected Initialize multiple Firebase projects for the Coinverse Android app to allow users to download the open sourced GitHub project as outlined in this StackOverflow answer. A

Solution 1:

Solutions

Issue 1

Each package may only be associated with one SHA-1 key. When removing the additional Firebase project and reverting the shared Firebase project to it's original state with the SHA-1 key the console provided the following error which revealed an issue.

An OAuth2 client already exists for this package name and SHA-1 in another project

This error message did not show originally, and would be useful to see the first time the same SHA-1 key is detected in a Firebase project with the same Android package name.

Solution

Remove the SHA-1 key from any other Firebase projects with the same package name. When using two Firebase projects in an Android application, they cannot use the same SHA-1 key.

Issue 2

The default Firebase project was not being generated from the google-services.json in the second newly created project.

Solution

Rebuild the project in Android Studio under Build > Rebuild Project