Google.Apis.Fitness.. net库:许可权不足[403]错误

我正在尝试使用google . api . fitness。在示例的最后一行出现权限错误(聚合请求执行)。我已经为我的项目启用了Fitness API。

如何解决这个错误?

string clientId = "MY_CLIENT_ID";//From Google Developer console 
string clientSecret = "MY_CLIENT_SECRET";//From Google Developer console 
string userName = Environment.UserName; 
string[] scopes = new string[] {
    FitnessService.Scope.FitnessActivityWrite,
    FitnessService.Scope.FitnessActivityRead,
    FitnessService.Scope.FitnessBodyWrite,
    FitnessService.Scope.FitnessBodyRead,
    FitnessService.Scope.FitnessLocationRead,
    FitnessService.Scope.FitnessLocationWrite
};
UserCredential _userCred = GoogleWebAuthorizationBroker.AuthorizeAsync(
    new ClientSecrets
    {
        ClientId = clientId,
        ClientSecret = clientSecret
    },
    scopes,
    "MY_USER",
    CancellationToken.None,
    new FileDataStore("Google.Fitness.Auth", false)).Result;

FitnessService _fitnessService = new FitnessService(new BaseClientService.Initializer()
    {
        HttpClientInitializer = _userCred,
        ApplicationName = "Fitness API Use",
    });

//Aggregate request
DateTime dt1970 = new DateTime(1970, 1, 1);
AggregateRequest agR = new AggregateRequest();
agR.AggregateBy  = new List<AggregateBy>();
AggregateBy oneAgrBy = new AggregateBy();
oneAgrBy.DataSourceId = "derived:com.google.step_count.delta:com.google.android.gms:estimated_steps";
oneAgrBy.DataTypeName =   "com.google.step_count.delta";
agR.AggregateBy.Add(oneAgrBy);
agR.BucketByActivityType  = new BucketByActivity();
agR.BucketByActivityType.MinDurationMillis = 5;
agR.StartTimeMillis = (long)(DateTime.Now.AddHours(-5) - dt1970).TotalMilliseconds;
agR.EndTimeMillis = (long) (DateTime.Now - dt1970).TotalMilliseconds;
UsersResource.DatasetResource.AggregateRequest agRequest =  _fitnessService.Users.Dataset.Aggregate(agR, "me");
AggregateResponse agResponse = agRequest.Execute();