Can't send mail error 550 and 554--unrecognized user or relay denied

I've done a clean install of server 10.4.11. When I try to send mail from my mobile me account tot he server I am getting one of two different errors: 550 unknown user, or 554 relay access denied. I'm dog tired after an all-nighter and not thinking clearly.

Here is my postconf -n output:

command_directory = /usr/sbin
config_directory = /etc/postfix
daemon_directory = /usr/libexec/postfix
debug peerlevel = 2
enable serveroptions = yes
html_directory = no
inet_interfaces = all
mail_owner = postfix
mailbox sizelimit = 0
mailbox_transport = cyrus
mailq_path = /usr/bin/mailq
manpage_directory = /usr/share/man
mydestination = $myhostname,localhost.$mydomain,localhost,mail.trinidadchroniclenews.com,trinid adchroniclenews.com
mydomain = mail.trinidadchroniclenews.com
mydomain_fallback = localhost
myhostname = mail.trinidadchroniclenews.com
mynetworks = 127.0.0.0/8
mynetworks_style = host
newaliases_path = /usr/bin/newaliases
queue_directory = /private/var/spool/postfix
readme_directory = /usr/share/doc/postfix
sample_directory = /usr/share/doc/postfix/examples
sendmail_path = /usr/sbin/sendmail
setgid_group = postdrop
smtpd clientrestrictions = permit saslauthenticated, permit_mynetworks, reject rblclient sbl-xbl.spamhaus.org reject rblclient list.dsbl.org reject rblclient bl.spamcop.net permit
smtpd pw_server_securityoptions = login
smtpd recipientrestrictions = permit sasl_authenticated,permit_mynetworks,reject_unauthdestination,permit
smtpd sasl_authenable = yes
smtpd tls_keyfile =
smtpd use_pwserver = yes
unknown local_recipient_rejectcode = 550
--------------

TIA

Rob