ASP.NET

System.Net.Mail.SmtpException: Syntax error, command unrecognized. The server response was: Microsoft Exchange Server 2003 POP3 server version 6.5.7638.1 (Mailserver.its.local) ready. at System.Net.Mail.SmtpConnection.GetConnection(String host, Int32 port) at System.Net.Mail.SmtpTransport.GetConnection(String host, Int32 port) at System.Net.Mail.SmtpClient.GetConnection() at System.Net.Mail.SmtpClient.Send(MailMessage message) at _Default.SendEmail(String from, String to, String cc, Int32 port, String subject, String message, String Host) in c:\Vuyiswa\Email_test\Default.aspx.cs:line 53

protected void Button1_Click(object sender, EventArgs e)
  {
      MailMessage mm = new MailMessage();

      SmtpClient smtp = new SmtpClient();

      mm.From = new MailAddress("Vuyiswa@its.co.za");

      mm.To.Add(new MailAddress("Vuyiswa@its.co.za"));

      mm.To.Add(new MailAddress("RDG@its.co.za"));

      mm.Subject = "Hello";

      mm.Body = "<p>This is the E-mail Test for !Booking System</p>";

      mm.IsBodyHtml = true;

      smtp.Host = "smtp.gmail.com";

      smtp.EnableSsl = true;

      System.Net.NetworkCredential NetworkCred = new System.Net.NetworkCredential();

      NetworkCred.UserName = "vuyiswamb@gmail.com";

      NetworkCred.Password = "secret";

      smtp.UseDefaultCredentials = true;

      smtp.Credentials = NetworkCred;

      smtp.Port = 587;

      smtp.Send(mm);
  }