I just use stalwart - mail, it’s just one docker container, has bleeding edge functions like jmap and there is no need of deeper knowledge. I refer my domain on the settings and got a list of all needed dns-records.
It takes 2-4 days to get SSL and dmarc answers from the big mail-players and if there is nothing wrong with your IP or your records then there is no mail going into spam of someone else.
I just use stalwart - mail, it’s just one docker container, has bleeding edge functions like jmap and there is no need of deeper knowledge. I refer my domain on the settings and got a list of all needed dns-records.
It takes 2-4 days to get SSL and dmarc answers from the big mail-players and if there is nothing wrong with your IP or your records then there is no mail going into spam of someone else.