Postfix problem with sending external emails <5.7.1 user@domain.com relay access denied>?

When sending mail using the mail program on the external email issues <5.7.1 user@domain.com relay access denied>. Sending to local mailboxes is successful. Send from the web interface also succeeds gage on the outer boxes.


cat /etc/postfix/main.cf

# See /usr/share/postfix/main.cf.dist for a commented, more complete version

# Debian specific: Specifying a file name will cause the first
# line of that file to be used as the name. The Debian default
# is /etc/mailname.
#myorigin = /etc/mailname

smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu)
biff = no

# appending .the domain is MUA''s job.
append_dot_mydomain = no

# Uncomment the next line to generate "delayed mail" warnings
#delay_warning_time = 4h

readme_directory = no
virtual_alias_maps = hash:/etc/postfix/virtual
sender_bcc_maps = hash:/etc/postfix/bcc
mailbox_command = 
home_mailbox = Maildir/
smtpd_sasl_auth_enable = yes
smtpd_sasl_security_options = noanonymous
broken_sasl_auth_clients = yes
smtpd_recipient_restrictions = permit_mynetworks permit_sasl_authenticated reject_unauth_destination
mydestination = server, localhost.localdomain, , localhost
mailbox_size_limit = 0
myorigin = $mydomain
relayhost = 
mynetworks = 127.0.0.0/8 83.52.232.16/28
recipient_delimiter = +
inet_interfaces = all
inet_protocols = ipv4