Missing incoming messages

[fredmartinmaine]

We have a 3rd party email gateway, which logged inbound emails to one of our public folders as being delivered successfully to our Exchange server.

However - the emails were not showing up in the public folder. We discovered fairly quickly that 'anonymous' lacked create items permission, it had been accidentally removed. Once that was fixed, email is now being delivered.

The issue is - for about 24 hours email to that public folder was logged by our gateway as delivered to Exchange - but they weren't delivered and no NDR was returned to the sender. I sent a test email from my home account, got no NDR. Where did these emails go?

Seems highly unlikely that Exchange would accept and then simply drop emails.

I discovered the SMTP send and receive connectors had the logging level set to None, so I have no logs there to review, unfortunately.

Looked in the Toolbox Queue viewer, I don't see any messages hanging in there.

Where do I look next?

Fred

 

[fredmartinmaine]

An update. I turned on the SMTP logs. I duplicated the error by removing create permission from the anonymous user and sent an email from outside our network, into the public folder. Then put the create permission back, and send a second test email.

As expected the first email was not delivered, the second one was. But in the SMTP log, both emails were accepted and queued for delivery.

?? Surely Exchange put that message somewhere, or if it dropped it, logged that event.

 

[fredmartinmaine]

So we've decided that there's no errors in the SMTP log because the emails must have been placed in the queue as it says it did. It follows that the issue is after the queue but before the final delivery location, which wasn't available. Apparently there's a 'store' of some sort that decides where/how to finally deliver the message. And, Exchange must have a log for that, if it's a separate process. No resolution yet.