I've also had luck with self-hosted solutions. Gawd, email is a really backwards technology these days isn't it? But...I've also been in the unfortunate posit

I've also had luck with self-hosted solutions. Gawd, email is a really backwards technology these days isn't it? But...I've also been in the unfortunate position of leasing IPv4 addresses which were already blacklisted by various sources. It's not a terribly easy problem to solve if you need to contact customers NOW without using a 3rd party solution.