Fitbit Google Login not working in iOS

[bharat8]

I'm currently facing an issue with Fitbit login on iOS devices. When attempting to log in using a Google account on the Fitbit OAuth page, the page keeps redirecting back to the Fitbit OAuth page after selecting google account, creating a loop. This behavior occurs only on iOS — everything works as expected on Android.

This is what my Authorization URL looks like: https://www.fitbit.com/oauth2/authorize?response_type=code&client_id=23Q3Y9&redirect_uri=mndprs-hesoyam38-fitbit://fitbit/auth&scope=activity%20cardio_fitness%20heartrate%20location%20nutrition%20profile%20settings%20sleep%20social%20oxygen_saturation%20respiratory_rate%20temperature&expires_in=10080

Minimal reproducible code

final fitbitCredentials = await FitbitConnector.authorize(
          clientID: clientId,
          clientSecret: clientSecret,
          redirectUri: myapp://fitbit/auth,
          callbackUrlScheme: myapp,
          expiresIn: 10080,
        );

print(fitbitCredentials);

Video link of what's happening -
https://drive.google.com/file/d/1yaQCkfgW11Q5yBz4zJSr2Z1Q83gsAbnv/view?usp=sharing

What I've Tried: The login flow works perfectly on Android. The issue only occurs on iOS when logging in with a Google account on the Fitbit OAuth page. No errors are thrown; it simply keeps redirecting back to the login page.

Question: What could be causing this redirect loop on iOS? Is there a platform-specific configuration or redirect URI handling issue that I might be missing?

Any help would be greatly appreciated!

[gcappon]

Hi! Question: does this work if you log in with your fitbit credentials instead?