CDO Question: transport failed to connect to the server

[Lori McDonald]

I have code that I am using to sent an HTML email. (see code below)

Intermittently I am getting the following error when I try and send an
email message from ASP.Net code on my server. 80% of the time it works
fine -- but 20% of the time it
fails with the following message:
The transport failed to connect to the server.

I am setting the mail server via the IP address. It actually is the
local mail server, but I didn't want to have any DNS resolution issues
-- so I don't understand how it could ever not connect.

It only seems to be happening for HTML formatted emails. I have
similar code in .Net that sends text messages and it is working fine.

I have enabled the website IP it is coming from for connection and
relay within the SMTP properties in IIS.

This sounds like a configuration issue, but I don't understand why it
would be intermittent. It only seems to happen from my ASP.Net code. I
have ASP mailers that are
not seeing this problem.

If you go back and try and resend the same email a minute or so later
it will send.

This has happened about 9 times (out of probably 50 emails) in the
last 3 months. So it is a problem. I keep trying fixes but it is so
intermittent I cannot tell if it is fixed for sure until we see the
error occur again.

When it occurs the page takes a long time (maybe 5 minutes) to reload
-- like it is trying to contact the server and not getting through.

Does anyone have any ideas what might be wrong or how I can
troubleshoot this?

Thanks,
Lori

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Dim mailMessage As New System.Web.Mail .MailMessage()

If From = "" Then 'Set default
mailMessage.Fro m = "Me <[e-mail]> "
Else
mailMessage.Fro m = From
End If

mailMessage.To = ToAddresses

mailMessage.Bcc = BCCs

If Not _arListAttachme nts Is Nothing Then
Dim myEnumerator As System.Collecti ons.IEnumerator =
_arListAttachme nts.GetEnumerat or()
While myEnumerator.Mo veNext()
mailMessage.Att achments.Add(Ne w
MailAttachment( myEnumerator.Cu rrent.ToString,
System.Web.Mail .MailEncoding.B ase64))
End While
End If

If LCase(Priority) = "high" Then
mailMessage.Pri ority = System.Web.Mail .MailPriority.H igh
ElseIf LCase(Priority) = "low" Then
mailMessage.Pri ority = System.Web.Mail .MailPriority.L ow
End If

mailMessage.Bod yFormat = System.Web.Mail .MailFormat.Htm l

Dim strBody As String
Dim strDBSubject As String

'This routine gets the Body of the message using a template database
driven system
GetMessage(strB ody, strDBSubject, intError)

If intError = 0 Then
mailMessage.Bod y = strBody

If Subject <> "" Then 'Set default
mailMessage.Sub ject = Subject
ElseIf strDBSubject <> "" Then
mailMessage.Sub ject = strDBSubject
Else
mailMessage.Sub ject = ""
End If

System.Web.Mail .SmtpMail.SmtpS erver = _strMailServer

System.Web.Mail .SmtpMail.Send( mailMessage)

End If