Replying through email suddenly stopped due to Let's Encrypt changes

[david (David Taylor)]

@PeterClamp

since 30th September 2021,

The timing suggests this is almost certainly caused by the letsencrypt certificate changes. You can find instructions for fixing the problem here:

Self-hosted mail-receiver update following Let's Encrypt root certificate change

This announcement only affects self-hosters who are running Direct-delivery incoming email for self-hosted sites. Managed hosting customers, and self-hosters using POP3 for incoming mail are not affected. As you may be aware, Let’s Encrypt recently changed their root certificate. The old root certificate expired today, and has caused a number of issues for out-of-date clients across the web. All of our systems at CDCK are up-to-date, and were not affected by today’s expiration. Unfortunately we…

Unfortunately there was no way for us to push out an automatic update for this problem, so an “Announcement” was the best we could do - sorry for the disruption!