Try commenting 'smtp_tls_security_level' parameter in Postfix config file /etc/postfix/main.cf.
Reference:
http://www.postfix.org/postconf.5.html# … rity_level
Try commenting 'smtp_tls_security_level' parameter in Postfix config file /etc/postfix/main.cf.
Reference:
http://www.postfix.org/postconf.5.html# … rity_level