Troubleshooting

Web: unregistered_origin

The current browser origin is not listed under Authorized JavaScript origins for the OAuth Web client ID.

Fix:

1. Log the exact window.location.origin.
2. Add that exact origin to Google Cloud Console.
3. Add http://localhost for local development.
4. Save changes and wait for propagation.
5. Hard refresh the app.

Web: GIS script cannot load

Check network access to:

https://accounts.google.com/gsi/client

Browser extensions, ad blockers, or corporate network rules can block it.

iOS: missing iosClientId

iOS requires an iOS OAuth client ID. Provide iosClientId, write GIDClientID to Info.plist, or bundle GoogleService-Info.plist.

iOS: redirect does not return to app

Check that the reversed iOS client ID URL scheme is registered in Info.plist. If using Expo, verify the config plugin ran and rebuild the native app.

Android: no credential found

If android.accountFilter is "authorized-first", the package falls back to all accounts when Android returns no credential. If sign-in still fails, check:

• Google Play Services availability.
• Correct package name.
• Correct SHA fingerprints.
• The OAuth Web client ID passed as webClientId.

Android: installed app mismatch

Google validates the installed app's package name and signing certificate. Add debug, release, and Play app signing fingerprints to Google/Firebase.

Expo: works on web but not device

Expo web only exercises the web implementation. Device builds need native setup and a rebuilt app.

The Expo Go native app cannot load the package's custom native module. Create an Android development build to test Google Credential Manager:

npx expo run:android

Use npx expo start --web to continue testing the web implementation.