Once in a while I get these notifications that the reply was not processed. I post a lot so I have no idea what reply by email wasn't posted.
Fortunately in a few cases I have been able to determine which post it was by cross referencing the outbox items to the time that the above message was received and have found that it was actually posted. I don't know if there were cases where it truely wasn't posted. I can't always be searching in times where this happens. It would be great if it would give me a second chance to try re-posting if it fails or at least give me the text that I attempted to post so that I can copy and paste when I am back at my computer.