> Your claim is "it is not possible to self-host your own mail on a low-volume server and not get consistently marked as spam by GMail / other large operators".

> Your claim is "it is not possible to self-host your own mail on a low-volume server and not get consistently marked as spam by GMail / other large operators". The existence of a single person successfully doing exactly that (and there are numerous such people in this very thread) is sufficient to disprove your claim. Perhaps that was their claim - but I've generally read advice as: "There's no predictable way to guarantee that any given person can today take over hosting their own mail with predictable and good delivery to Gmail and o365." So just that a, b and c have, so far, good delivery from their setup is not a guarantee that person x can just "set things up correctly" and somewhat straightforwardly get good delivery. Last I did it, I had to go via undocumented api/pages for both o365 and Gmail in order to improve delivery - and mail that gmail/o365 smtp servers swore they accepted without problems - still sometimes ended up as spam, or simply vanished after delivery. This was all individual low-volume. Never found any reason for it. That said, I'll probably go back to hosting my own mail, and just live with certain parties being bad net citizens, eating the occasional mail without error or bounce. It's not like I really expect them to do better. Although especially in the case of Gmail, it's a little like Disney eating up public domain stories and spitting out copyrighted and trademarked content. Google did a lot to force people away from proper quoting (by hiding the fact of how Gmail quoted things in the "friendly" ui) and they pretty much killed Google groups - after marginalizing alternatives. But those ships have sailed.