For a Flutter mobile app I am trying to use a Microsoft OAuthProvider to get a Firebase credential with which to sign the user into Firebase with their Azure AD account.
The closest I got was using a third party Active Directory auth package to log the user in and get an access token. However the sign-in to Firebase fails with an error message that suggests the idToken is invalid.
final AadOAuth oauth = new AadOAuth(config);
await oauth.login();
// accessToken looks legit
String accessToken = await oauth.getAccessToken();
String idToken = await oauth.getIdToken();
OAuthProvider provider = OAuthProvider('microsoft.com');
// Also tried the constructor without the idToken
OAuthCredential credential = provider.credential(accessToken: accessToken, idToken: idToken);
// app fails here:
await FirebaseAuth.instance.signInWithCredential(credential);
// this works fine, but only on web platform:
await FirebaseAuth.instance.signInWithPopup(provider);
Because it is a platform specific error (iOS in this case), the exception details are not surfaced. All I get is:
PlatformException(internal-error, ) nativeErrorCode: 17999
Here is my app settings in the Azure portal:

Full manifest here
Has anyone been successful in using Microsoft Auth to sign a user in to Firebase in a Flutter mobile app?
