I have reply-by-email set up working back in June with the mail receiver docker container. I’m not sure what has happened (I haven’t done any upgrade since), but the server can no longer process incoming emails.
Mail receiver log:
<23>Sep 16 05:47:49 receive-mail[5333]: Recipient: replies+de9850e89875889b6f8c13d7a9de6d18@url-redacted
<19>Sep 16 05:47:50 receive-mail[5333]: Failed to POST the e-mail to https://<url redacted>/admin/email/handle_mail: 400
Discourse log
Started POST "/admin/email/handle_mail" for 172.17.0.1 at 2021-09-16 08:14:36 +0
000
ActionController::BadRequest (Invalid request parameters: Invalid encoding for parameter: Received: from MTA-11-3.url-redacted (mta-11-3.
by discourse-ubuntu-nyc1-mail-receiver.localdomain (Postfix) with ESMTPS id B234513F82C
for <replies+de9850e89875889b6f8c13d7a9de6d18@<url-redacted>>; Thu, 16 Sep 2021 05:47:49 +0000 (UTC)