Does your master.cf in /etc/postfix looks like this?
smtp inet n - n - - smtpd
-o content_filter=smtp-amavis:127.0.0.1:10024
-o receive_override_options=no_address_mappings
#
## Enable SMTP on port 587 only for authenticated/TLS clients
submission inet n - n - - smtpd
-o smtpd_enforce_tls=yes
-o smtpd_sasl_auth_enable=yes
-o smtpd_client_restrictions=permit_sasl_authenticated,reject
## Enable SMTP on port 465 only for authenticated/SSL clients
smtps inet n - n - - smtpd
-o smtpd_tls_wrappermode=yes
-o smtpd_sasl_auth_enable=yes
-o smtpd_client_restrictions=permit_sasl_authenticated,reject