Enable SMTPS Port 465 in Postfix SMTP Server For Email Submission
In previous articles, we discussed how you can quickly set up your own mail server by using iRedMail or Modoboa, and also how to set up mail server from scratch on Ubuntu. This tutorial will be showing you how to enable SMTPS port 465 in Postfix SMTP server, so Microsoft Outlook users can send emails. SMTPS stands for Simple Mail Transfer Protocol Secure.
Read the full guide there: https://www.linuxbabe.com/mail-server/enable-smtps-port-465-postfix