Don't host email yourself – your reminder in 2026

The solution to "my transactional email service does not deliver to one ISP" is "use a transactional email service". I have used transactional email services for low volume and highly variable sites and have had very few problems, none of them general blocks - there were warnings from providers and a single digit number of hard bounces when one site had a vulnerability to registration spam (owner thought the previous developers had a honeypot to stop it, turned out it not so).

Its very weird that low volumes are the problem. I have been self-hosting personal email for myself and a few family members (so very low volume) on an OVH VPS for years. I cannot deliver to Hotmail (MS hosted institutional email works, outlook.com works) but that is the only problem and I can live with that for personal email.

I’ve been self-hosting my personal email for over 20 years, but I would never use it to send transactional mail. That belongs on a different domain using an ESP that has the reputation for it (I prefer Postmark).

And yet email addresses being domain specific also makes it impossible for end users of popular service providers to migrate to another service, unless they are using their own domain name.