Poste.io – Complete Mail Server
I feel like this solution is optimizing the wrong problem.The bulk of work with managing a mail server (these days) isn't software setup and admin. On the receiving side, it's all the work dealing with abuse and attacks. On the sending side -- and this is the tough one -- it's getting sites to accept your email. When I finally gave up managing my own mail server (about two years ago), I found that about every six months I was involved in some panic where some large mail provider (Microsoft and Google most frequently) decided they didn't want to accept email from my server. Solving these issues is neither easy nor quick.These days I'm very happy to pay somebody else to run email services using my provided domains.