Trying to renew SSL certificates on Dwellers, the server hosting mail server, I've noticed bioty.co domain has expired.
$ letsencrypt renew 1 renew failure(s), 0 parse failure(s) IMPORTANT NOTES: - The following errors were reported by the server: Domain: mail.bioty.co Type: unauthorized Detail: Invalid response from http://mail.bioty.co/.well-known [...]