Fix Android Google Login Failure

My Android app’s Google-based sign-in has stopped working. When a user chooses a Google account, the callback never supplies a valid token so they’re bounced back to the login screen. Traditional email/password flow remains fine; the fault is limited to the Google third-party authentication.

The codebase is native Android (Kotlin and a small amount of Java) and currently uses the Google-Sign-In API bundled with Play Services. I suspect a recent API/SDK change, an SHA-1 mismatch, or a token parsing issue, but I need a fresh set of expert eyes to pinpoint and fix it.

What I need from you
• Review the existing authentication module, console configuration and SHA fingerprints
• Update or refactor the Google Sign-In flow so it retrieves a valid ID token and user profile every time
• Provide a clean pull request or zipped module with concise comments on the changes
• Prove the fix with a short screen-capture or log demonstrating a successful login on a device running Android 13 (emulator or physical)

Deliverable is the corrected source plus a brief summary of what was broken and how you resolved it. Once the updated build lets new and returning users authenticate via Google without errors, the job is done.