Symptoms
-
Emails sent to an external account such as Gmail, shows the following message:
security: example.com did not encrypt this message
-
Mail is not delivering with the following message in /var/log/mailllog:
status=deferred (delivery temporarily suspended: TLS is required, but was not offered by host 127.0.0.1[127.0.0.1])
Cause
Incorrect Postfix configuration.
-
Parameter
smtp_tls_security_level = may
is missing in the/etc/postfix/main.cf
:# grep smtp_tls_security_level /etc/postfix/main.cf