Returning to this old thread, as my organization has moved its mailing
to yet another monster (namely https://outlook.office.com).
The problem was actually the "smtps://" as opposed to "smtp://"
https://unix.stackexchange.com/questions/66560/mutt-smtp-tls-error-sending-mail
doscribes it as
Strange as "openssl s_client -starttls smtp -connect mail.cvut.cz:587"
works for me, can you try that yourself in case there's any different
config for local clients and that fails for you? (It's also possible they
have fixed the server by now :-)
LibreSSL doesn't support SSL, only TLS, so
This is mutt-1.14.6v3-sasl in 6.7-current/amd64.
Recently, my institution's mail has been moved to
220 mail.cvut.cz Microsoft ESMTP MAIL Service
Trying to send mail through it fails with
SSL failed: error:1404B42E:SSL routines:ST_CONNECT:tlsv1 alert protocol version
I enabled all the following