[feanaro]

My email server is only used as a personal server for a few select friends and family. They absolutely do not send and have never sent anything that could remotely be considered spam. Everything in our setup is picture perfect (SPF, DKIM, DMARC, PTR records, etc). We still can't get email onto Microsoft's servers without it being marked as spam.

[Retric]

Interesting, marked as spam in peoples inbox is different from simply never showing up which is what happens to the vast majority of spam.