Well, there is always the excellent mail-tracking and mail-journaling capabilities that are built in Domino.
Especially the mail tracking will tell you the exact routing path, and if the user has deleted the mail in their inbox or not.
For an asp.net based solution, that's a different story of course. But maybe the smtp-server you are using has a similar function too. Most smtp-servers have logging-functionality built-in.
Well, there is always the excellent mail-tracking and mail-journaling capabilities that are built in Domino.
Especially the mail tracking will tell you the exact routing path, and if the user has deleted the mail in their inbox or not.
For an asp.net based solution, that's a different story of course. But maybe the smtp-server you are using has a similar function too. Most smtp-servers have logging-functionality built-in.