The trick to this is not hosting your mail server with a provider which has a bad reputation.
Mine goes through a DigitalOcean droplet and my mail usually gets through (based on the assumption that if I received a reply, the other person must have received it!)
By contrast a volunteer group I'm involved with was using OVH "because it's the cheapest". Suppliers and customers were routinely telling us the emails were going to spam. Moved to another provider (no idea who, the infrastructure team does that) and the complaints fell to a trickle.
Good IP block reputation (check RBLs) + valid SPF + valid DKIM is usually enough to get mail through. Except occasionally to Hotmail... but that's Hotmail...
Mine goes through a DigitalOcean droplet and my mail usually gets through (based on the assumption that if I received a reply, the other person must have received it!)
By contrast a volunteer group I'm involved with was using OVH "because it's the cheapest". Suppliers and customers were routinely telling us the emails were going to spam. Moved to another provider (no idea who, the infrastructure team does that) and the complaints fell to a trickle.
Good IP block reputation (check RBLs) + valid SPF + valid DKIM is usually enough to get mail through. Except occasionally to Hotmail... but that's Hotmail...