By default, virtual servers aren’t setting up SMTP to use SSL. Following this information regarding SSL SMTP I am just summarizing:
netstat -an | grep :465
Returns nothing, so.
vi /etc/postfix/master.cf
find the lines:
#smtps inet n - n - - smtpd # -o smtpd_tls_wrappermode=yes # -o smtpd_sasl_auth_enable=yes # -o smtpd_client_restrictions=permit_sasl_authenticated,reject # -o milter_macro_daemon_name=ORIGINATING
And uncomment them: