Problem sending Email from VB.NET application

Hello,

This is a problem with a simple DOT NET 2 application which sends email using system.net.mail.  The email has a small PDF attachment.

It works fine here at my office on my notebook with a nuber of SMTP servers and two different ISP's.

However at the client's site (I change the SMTP server/port to the one they need to use), the email function hangs the application with no error trapped.    In the meantime while I am waiting I cannot end the process even if I use task manager.  i have to restart the computer.

I can ping the mail server and get the three expected replies.

At a command prompt I can use telnet to send an email.

I am not sure where to begin to diagnose the problem.   It is on a large corporate network and I cannot hook my notebook into it and they are locked down so I cannot install another email client to test.    

I have tried lowering the timeout value on the smtpclient and it made no difference.

Any Ideas?

Thanks,

Stephen Simpson

Imports system.net.mail
 
Try
         Dim eMail As New MailMessage
         With eMail
 
              .From = New System.Net.Mail.MailAddress(sEmailReplyTo)
 
              Dim recipient As System.Net.Mail.MailAddress = New System.Net.Mail.MailAddress(Trim(sEmail))
              .To.Add(recipient)
 
              .Subject = "Report for " & sLocation
              .Body = _
              "Attention: " & sContact & vbCrLf & _
              "Subject: Test " & vbCrLf & _
              "Location: " & sLocation & vbCrLf & _
              "Call Date: " & sCallDate & vbCrLf & vbCrLf & _
              sTextOfEmail
 
              .Attachments.Add(New Net.Mail.Attachment(di.FullName & "\" & Trim(sAttach)))
 
               .IsBodyHtml = False
          End With
 
         Dim smtpclient As New System.Net.Mail.SmtpClient
         smtpclient.Host = sSMTPServer 
         smtpclient.Port = sSMTPPort '1025
 
         If sSMTPUser <> "" Then
                smtpclient.Credentials = New System.Net.NetworkCredential(sSMTPUser, sSMTPPassword)  
         End If
 
         smtpclient.Send(eMail)
 
         eMail.Dispose()
 
Catch exEmail As Exception                    
           DisplayStatus("Email processing failed while processing:" & vbCrLf & sTrans & vbCrLf & exEmail.Message, True)
End Try 
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