Flutter:Firebase ab test - Error saving test devices: Something went wrong

[tazik561]

I am trying to Firebase use remote config ab test on my simple application .So after add all dependencies and ready my console i created my remote config. I test my remote config and everything was good. Now i create AB test. After added variant and goals now i am trying to add my token user id. I get my token from this code:

   FirebaseAuth.instance.signInAnonymously().then((value) async {
      String token = await value.user.getIdToken();
      print("-------> token Auth: $token");
    }).catchError((onError) => print(onError));

Now, in Test devices for Experiment, i am trying to add may token :

as you can see i got Error saving test devices: Something went wrong error!

My token has a problem? :