I configurated postfix to force uses TLS. When an external client try to send an email using this server there is not any problems. But using webmail (127.0.0.1) postfix wants TLS:

delivery temporarily suspended: TLS is required, but was not offered by host 127.0.0.1[127.0.0.1])

Which changes I need to do to master.cf?

smtp_use_tls = yes
smtp_tls_security_level = encrypt
smtpd_use_tls = yes
smtpd_tls_auth_only = yes
smtpd_tls_key_file = /etc/postfix/ssl/xxx.key
smtpd_tls_cert_file = /etc/postfix/ssl/xxx.crt
smtpd_tls_loglevel = 1
smtpd_tls_received_header = yes
smtpd_tls_session_cache_timeout = 3600s
tls_random_source = dev:/dev/urandom
smtpd_tls_session_cache_database = btree:${queue_directory}/smtpd_scache
smtp_tls_session_cache_database = btree:${queue_directory}/smtp_scache