https://meta.discourse.org/t/emails-stopped-working-failing-after-upgrade/227502/3?tl=en
Emails stopped working, failing after upgrade - #3 by JammyDodger - Self-hosting - Discourse Meta
May 19, 2022 - After upgrading to 2.9.0 beta4, our emails started failing. Is there a major change to cause that? It seems the issue is with SSL? We use Ehlo as SMTP to HTTP...