Re:Maddy: Composable all-in-one mail server
by g_p on Saturday June 19, 2021 @07:19AM
(#27559592)
Your symptoms sound exactly like the issues I was having - everything was "right" (in theory) - emails were leaving on the right IPv4, that had the correct PTR, etc etc. I just couldn't figure out what was wrong.
It was the same issue - even replies to existing threads had the issue. What got me looking into it more closely was that I had no issues delivering to G Suite tenants; it was only issues with 365 tenants.
I wonder if there's a non-trivial correlation between people choosing to genuinely self-host their own mail, and those who use plaintext outbound mail by default (and know what that means).
It was the same issue - even replies to existing threads had the issue. What got me looking into it more closely was that I had no issues delivering to G Suite tenants; it was only issues with 365 tenants.
I wonder if there's a non-trivial correlation between people choosing to genuinely self-host their own mail, and those who use plaintext outbound mail by default (and know what that means).