Sending Emial Error

Hi,

I am busy with an application that needs to send an email through my company's exchange server. But when my application tries to send the email I get the following error:

The following exception occurred: System.Net.Mail.SmtpException: Failure sending mail. ---> System.Net.WebException: Unable to connect to the remote server ---> System.Net.Sockets.SocketException: No connection could be made because the target machine actively refused it

Here is the code that I am using:

using System;

using System.Collections.Generic;

using System.Text;

using System.Net.Mail;

using System.Net;

using PMonThread.Properties;

namespace PMonThread

class EMail

   public void SendEMail(string body, string subject)

      // initializes the mailmessage object and adds the appropriate values

      MailMessage mail = new MailMessage();

      mail.From = new MailAddress("");

      mail.To.Add("");

      SmtpClient smtp = new SmtpClient("");

      try

      }catch (Exception ex)

         throw ex;