I'm aware of lots of ways in which Microsoft refuses to receive mail *FROM* one's own domain. I've got all those hammered down. However, for the past few months I've been struggling to get mail from Microsoft to deliver *into* my system. I've been running essentially the same Postfix environment for many years and it works perfectly fine when mail comes in from every other provider I can imagine. Microsoft, however, refuses to deliver mail to me. That is: until I put my MX on a different IP, like my residential IP for my home internet connection. No issues whatsoever there. The pattern is always the same: Microsoft connects from some outlook.com hostname, establishes TLS, and then disconnects without doing anything. As soon as I flip my MX to a cloned instance of my existing MX behind a different IP, mail delivery does happen just fine.
Any ideas?
Any ideas?