Hi,

 I have created a windows application to send emails using vs 2005 in
vb.net. I am having problems sending the emails. The operating system on
which this application is run is windows vista business. we have an exchange
server 2007 that is in the same network. I am trying to send the emails using
the exchange server with the following code.

Private Sub btnSendEmail_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles btnSendEmail.Click
       Dim errMsg As String
       Dim ToAddress As String
       Dim FromAddress As String
       'Dim mailman As New Chilkat.MailMan
       Try
           ToAddress = "to@mycompany.com"
           FromAddress = "from@mycompany.com"
           Dim mm As New MailMessage(FromAddress, ToAddress)

           mm.Subject = "Test"
           mm.Body = "Test Email"
           mm.IsBodyHtml = False

           Dim smtp As New SmtpClient
           smtp.Host = "exchangeserver ip address"
           smtp.Port = 25
           'smtp.se()
           smtp.Credentials = New
System.Net.NetworkCredential("exchangeserveripaddress\myusername",
"mypassword")
           smtp.UseDefaultCredentials = False
           smtp.DeliveryMethod = SmtpDeliveryMethod.Network
           Try
               smtp.Send(mm)
           Catch ex As Exception
               errMsg = ex.ToString()
           End Try

       Catch ex As Exception

       End Try

Following is the error that I am receiving when I run the code.

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
  at System.Net.Sockets.Socket.DoConnect(EndPoint endPointSnapshot,
SocketAddress socketAddress)
  at System.Net.Sockets.Socket.InternalConnect(EndPoint remoteEP)
  at System.Net.ServicePoint.ConnectSocketInternal(Boolean connectFailure,
Socket s4, Socket s6, Socket& socket, IPAddress& address, ConnectSocketState
state, IAsyncResult asyncResult, Int32 timeout, Exception& exception)
  --- End of inner exception stack trace ---
  at System.Net.ServicePoint.GetConnection(PooledStream PooledStream,
Object owner, Boolean async, IPAddress& address, Socket& abortSocket, Socket&
abortSocket6, Int32 timeout)
  at System.Net.PooledStream.Activate(Object owningObject, Boolean async,
Int32 timeout, GeneralAsyncDelegate asyncCallback)
  at System.Net.PooledStream.Activate(Object owningObject,
GeneralAsyncDelegate asyncCallback)
  at System.Net.ConnectionPool.GetConnection(Object owningObject,
GeneralAsyncDelegate asyncCallback, Int32 creationTimeout)
  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)
  --- End of inner exception stack trace ---
  at System.Net.Mail.SmtpClient.Send(MailMessage message)
  at WindowsApplication1.Form1.btnSendEmail_Click(Object sender, EventArgs
e) in C:\Users\sduggireddy\Documents\Visual Studio
2005\Projects\WindowsApplication1\WindowsApplication1\Form1.vb:line 162

I am not knowing how to debug this. Please let me know.

Thanks