Another Gmail-to-SimAuthor test came back with two words:
Got it.
I had been doing the same thing for weeks. Gmail to SimAuthor. SimAuthor back to Gmail. test. RE: test. Good to go. Yep got it.
I did not put the configuration change in the message. It may have been Outlook, routing, DNS, filtering, or forwarding. The mail itself was the check.
This one left Gmail, reached SimAuthor, and made it back again. Good enough for Valentine's Day.
More tests followed the next morning.
This was not the first run. January had messages in both directions. Some came back with Good to go. Others said Yep got it. The same personal Gmail account and my SimAuthor Network Administrator address kept trading short confirmations across different days.
That repetition means I was checking the path after more than one change or from more than one setup. It does not tell me which one. I did not save a ticket with the messages, and the bodies never name Outlook, a relay, an alias, a spam rule, or a DNS record.
At SimAuthor, email was one service inside a mixed Windows and Linux office. Delivery depended on the client, the mail system, DNS, filtering, firewall rules, and the connection to the outside world. A round trip did not explain every part, but it narrowed the place to look next.
I kept the test messages short because the result was the content. If the message arrived, reply. If the reply arrived, the path worked in both directions. Then change the next thing and do it again.
The February 14 round trip worked. I checked again on February 15.