Pre-Check Before Configuring Google SignIn
Google SignIn in Web is Configured
Web Client ID configured for Google SignIn in web and Mobile app Builder should be same.
Admin Panel -> Websites and Apps -> Mobile App Builder

- Bundle ID Used in App-Builder and App Package in Google Play Console should be same.

SHA-1 Keys Configuration Navigations
Google Play Console
- Google Play Console > Select App > Setup > App Integrity
Google Cloud Console
- Google Cloud Console > API’s & Services > Credentials
Step 1 :
Create Android Client ID Credentials under the same project where Web-Client ID and API Keys are configured for Google Sign In for Web

Click On Create Credentials > OAuth client ID
Select Application Type as Android > Enter App Package name(bundle_id) > Get SHA-1 Keys from Google Play Console (SetUp > App Integrity > App Signing Key Certificate >SHA-1) > Create

Repeat the same step of creating Android Client ID for Upload Key Certificate as well.

On Completing the above configurations, Google Signin in Mobile application should be working fine. In Case if still there are issue being faced, please recheck with the Web-Client ID’s, Package names, Google Cloud Project.
Google Consent Screen Verification process and Publishing status from Testing to Production
Google Cloud Console > API’s & Services > OAuth Consent Screen
Change Publishing status of app from Testing to Production
Click On Prepare for Verification
Enter all necessary details with respect to Application and send for verification and submit for verification.