exception sending SMS message using WAY2SMS

Question

I have written the following code to send an SMS through Way2Sms site but the sms fails to go

        try
        {
            Way2Sms oway2 = new Way2Sms(LoginIDofWay2smssite, passwordofWay2smssite);
            oway2.Login();
            oway2.SendSms(MobileNumberofsmstobesend, Messagetobesent);
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
        }   

I get the error message "Login denied"

    1.  LoginIDofWay2smssite / passwordofWay2smssite    -   are correct
    2.  
        A.  I have included the following DLLs  in my project 
                -   CsQuery
                -   Nitin.Sms.Api
                -   SmsClient
                -   SMSClassLibrary

        B.  Added references to the above DLLs

        C.  specified the following using statements

                using System;
                using System.ComponentModel;
                using System.Data;
                using System.Data.SqlClient;
                using System.Windows.Forms;
                using SmsClient;
                using System.Net;
                using System.Net.Mail;
                using WhatsAppApi;
                using Nitin.Sms.Api;
                using System.Text.RegularExpressions;

    3.  I have logged in to the WAY2SMS site using the above ==>  LoginIDofWay2smssite / passwordofWay2smssite 
        I have been able to successfully Login and send the above  test message - Messagetobesent -  to the above mobile number => MobileNumberofsmstobesend

Please help me to solve this problem and thanking you in advance

regards Manoj Gokhale