You have added the Google Play Services plugin to the project, which reads from the google-services.json
found in your app module.
The google-services.json
contains service configuration data, such as Google Project ID, application package name, etc..
Since the application package name is also stored in that json, it will not match anymore, so you have to create a new application in your Firebase console, and export the new configuration json.
Then replace the google-services.json
in your project with the one you have generated.