For example, something that is too complex for your comfort level, a security concern, or maybe your hardware can’t keep up with the service’s needs?
For example, something that is too complex for your comfort level, a security concern, or maybe your hardware can’t keep up with the service’s needs?
With DKIM and SPF, I’ve had zero problems in the last 15 years of selfhosting, most recently with Mailcow Docker on a residential IP. I don’t even have a reverse PTR to my mailserver hostname, just a PTR provided by the ISP that can be resolved.
I’ve added a few fresh, un-reputed domains to the server and had no issues.
I think many people’s problems with running email servers are self-inflicted. I remember even before there were things like blacklists, etc with large providers, many people had problems keeping mailservers running. It’s just not an easy task for a variety of reasons completely unassociated with the mega’s blacklisting you. I’ve been running mailservers at various scales for 20+ years so maybe it’s just second nature to me now.