problem connection to mail server using system.net.mail

We are currently using VB.NET 2.0 in VS 2005 and have attempted to use the new System.Net.Mail framework to send SMTP mail.  Also, our email server requires smtp authentication.

Unfortunately, we continue to receive the following error:

Server Error in '/ESB3' Application.
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A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Net.Sockets.SocketException: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond

Source Error:
An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:
[SocketException (0x274c): A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond]
   System.Net.Sockets.Socket.DoConnect(EndPoint endPointSnapshot, SocketAddress socketAddress) +1002146
   System.Net.Sockets.Socket.InternalConnect(EndPoint remoteEP) +33
   System.Net.ServicePoint.ConnectSocketInternal(Boolean connectFailure, Socket s4, Socket s6, Socket& socket, IPAddress& address, ConnectSocketState state, IAsyncResult asyncResult, Int32 timeout, Exception& exception) +431

[WebException: Unable to connect to the remote server]
   System.Net.ServicePoint.GetConnection(PooledStream PooledStream, Object owner, Boolean async, IPAddress& address, Socket& abortSocket, Socket& abortSocket6, Int32 timeout) +1447736
   System.Net.PooledStream.Activate(Object owningObject, Boolean async, Int32 timeout, GeneralAsyncDelegate asyncCallback) +190
   System.Net.PooledStream.Activate(Object owningObject, GeneralAsyncDelegate asyncCallback) +21
   System.Net.ConnectionPool.GetConnection(Object owningObject, GeneralAsyncDelegate asyncCallback, Int32 creationTimeout) +318
   System.Net.Mail.SmtpConnection.GetConnection(String host, Int32 port) +227
   System.Net.Mail.SmtpTransport.GetConnection(String host, Int32 port) +316
   System.Net.Mail.SmtpClient.GetConnection() +42
   System.Net.Mail.SmtpClient.Send(MailMessage message) +1485

[SmtpException: Failure sending mail.]
   System.Net.Mail.SmtpClient.Send(MailMessage message) +2074
   Modules_General_ForgotPassword.EmailNewUnhashedPwd(String UserID, String UnhashedPwd, String ToAddress) +420
   Modules_General_ForgotPassword.RequestNewPassword(String UserID_or_Email) +559
   Modules_General_ForgotPassword.btn_RequestNewPwd_Click(Object sender, EventArgs e) +48
   System.Web.UI.WebControls.Button.OnClick(EventArgs e) +105
   System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument) +107
   System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +7
   System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +11
   System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +33
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +5102

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Version Information: Microsoft .NET Framework Version:2.0.50727.42; ASP.NET Version:2.0.50727.42



Here is a sanitized version of the code used to generate the email.

Dim mailMessage As Net.Mail.MailMessage = New Net.Mail.MailMessage
        mailMessage.From = New Net.Mail.MailAddress("xyz@company.com")
        mailMessage.To.Add(New Net.Mail.MailAddress("john.doe@company.com"))
        mailmessage.Subject = "This is the subject."
        mailMessage.Priority = System.Net.Mail.MailPriority.High
        mailMessage.IsBodyHtml = True
        mailmessage.Body = “<B>Hello World</B>”
        Dim mailClient As New System.Net.Mail.SmtpClient("mail.company.com", 25)
        mailClient.Credentials = New Net.NetworkCredential("(username)", "(password)")
        mailClient.UseDefaultCredentials = False
        mailClient.Send(mailMessage)
        mailMessage.Dispose()


Thanks in advance,
-Tim