I have seen so many emails detected by Secure Messaging Gateway. But, unfortunately, almost all detections was wrong. For example, it mentioned the messages were detected as they had the fingerprint of the executable file, but actually no attachment. As this system doesn't send any notification when detecting something, sometimes I haven't been aware of the emails from our customers. That is a very critical situation. The white list doesn't work well. Without the notification, I need to login to this system more than once a week... Please add the notification feature for the users.
I'm not sure if I have the same problem but it sounds similar. SMG is used here as outbound relay. Message tracking shows if outbound mails are deliverable. However if someone's mail has been blocked because of blacklisting the only possibility to find out is message tracking. There is no notification in case of these troubles.
Unfortunately some providers put new SMTP servers on blacklists.