I did some testing with forced TLS and I expected to receive the error message in Outlook indicating that the domain I was forcing was not TLS (it is in the logs) but instead I received a delayed delivery message. Has anyone else seen this type of problem?
I was thinking of creating a new mail notification for this error to see if this resolves the problem.
What hotfix are you running? I think that is something that should come back right away with a failure, and I know there were several issues with SMTPO for a while.