The DSNEnvID property specifies the message envelope ID as defined in RFC1891.
Sets or returns a String value.
The String may contain up
to 100 characters (any ASCII characters between "!" (33) and "~" (126), except for "+" and "=")
DSN stands for "Delivery Status Notifications", it is an ESMTP
extension that is implemented by most modern SMTP servers. See RFC1891
for details.
Sub Mail_OnStartRender()
' Save the database contact ID in the ESMTP DSN Envelope-ID
to
' update the database later using the DSN message
Mail.DSNEnvID = Record.Fields("ContactID")
Mail.DSNNotify = "SUCCESS,FAILURE"
End Sub