Does “System.Net.Mail.DeliveryNotificationOptions” only work with Exchange?

Question

We have an application that is running on a SharePoint 2010 server that sends an email. We (the sender) want to receive delivery notifications but we are unable to retrieve them

Answer 1

Could you try adding a "Return-Receipt-To" address in case the mail server in use at the customer site requires it?

AFAIK, the .Net.Mail is using standard SMTP calls but not all SMTP servers are created equally....