Even though email is supposedly “open”, and federated, is no longer is really the case. Big services like Gmail are suspicious of non-big-name servers, and often flag email coming from them as spam.
About a year ago I came across an article from a guy who’d been running his own email server since the 90s, and finally gave up. I couldn’t find that article in my quick search, but I did find this:
https://twitter.com/greg_1_anderson/status/1425113874722820100
“I run my own email server. It’s no longer a good idea, because the anti-spam arms race makes delivery from small independent servers very difficult, even when you keep yourself off the block lists, so it’s a continuous struggle. Would switch, but I have too many domains/addresses”
This is very true, I have hosted my own email before and if you are doing it yourself and not going through a big player like google to host it then your stuff sometimes gets treated as suspect by filters. Used to beg people with Gmail accounts to flag my emails as “not spam” whenever it showed up in the spam folder.
