I have developed a Fitbit app to go alongside our iOS and Android app. I am using the Oauth component in the settings to connect to our AWS Cognito login, which also has Facebook and Sign in with Apple as IDP options. It seems that our iOS users are unable to use the Sign in with Apple function to authenticate their accounts. Reports are indicating that after completing authentication with Sign in with Apple, the user is prompted to return back to the Fitbit app and are still not logged in.
I had similar issues in the past with Facebook when I originally didn't include "encodeAsBase64" in the properties of the Oauth component and the redirect callback would fail. This case seems to be iOS specific as I was able to go through the Sign in with Apple flow in both the Fitbit simulator and Android without failure. I am in the process of getting an iOS device for testing this personally, but I was curious if there was any additional insight that could be provided as to why the redirect callback is failing.
