API validation error on Enrol and activate SMS factor

Questions
1

Hi,

I am trying to consume Okta .net sdk from my C# code for basic CRUD operations which are working fine. I am running into API validation issue when I try to enrol and activate SMS factor after successful user creation.
Se my code below - (I am getting API validation error when I try to call addfactorasync)

    private static IUser SendCreateUserRequestToOktaAsync()
    {
        try
        {
            var task = Task.Run(async () => await CreateUser());
            task.Wait();
            IUser result = task.Result;
            if (!string.IsNullOrEmpty(result.Id))
            {
                EnrollSMSFactor(result);
            }
            return result;
        }
        catch (Exception e)
        {
            Console.WriteLine("User Creation failed with error :" + e.InnerException.Message);
            Console.WriteLine("User Name :" + strfirstname + " " + strlastname);
            LogWriter.WriteLog("User Creation failed with error :" + e.InnerException.Message);
            LogWriter.WriteLog("User Name :" + strfirstname + " " + strlastname);
            //LogWriter.WriteLog("User Last Name :" + strlastname);

            return null;
        }

    }

    private static void EnrollSMSFactor(IUser usr)
    {
        var task = Task.Run(async () => await client.UserFactors.AddFactorAsync(usr.Id, new AddCallFactorOptions() { PhoneNumber = "0474800999",PhoneExtension = "61" }));
        task.Wait();
        IFactor result = task.Result;
        ActivateSMSFactor(usr, result);
    }
    private static void ActivateSMSFactor(IUser usr,IFactor factor)
    {
        VerifyFactorRequest req = new VerifyFactorRequest()
        {
            ActivationToken = factor.MfaStateTokenId,
            //Answer = factor.,
            //NextPassCode = ,
            //PassCode = ,
            TokenLifetimeSeconds = factor.TokenLifetimeSeconds };

        var task = Task.Run(async () => await client.UserFactors.ActivateFactorAsync(req, usr.Id,factor.Id));
        task.Wait();
        IFactor result = task.Result;
    }