Does it sit behind a clean IP? Had any problems sending to gmail or other big providers?
Not really an issue for me since I am not using it for mass marketing; and it’s just a personal email server. So just a single user (me).
There were issues with block lists and outlook but was fixed after IP reset. Fortunately most of these services provide near instant feedback via mail protocol or bounced emails.
Plus I have a metrics exported via Prometheus and feeding into influx db and grafana dashboard.
Also fun to monitor Dovecot and postfix logs and get them into grafana. The number of script kiddies just sending random requests is fun to watch. Had a couple of instances where attacker was clearly trying to find a vulnerable user and try to use my server for spam or something else.
I think linode may have had problems in the past with their assigned ip ranges being used as spam. Quickly looking into it, seems like they block outgoing email traffic by default now. But individual server owners need to manage IP rep.