It appears your server does not see itself as a destination for the email it's receiving. .
I would verify the following items to start.
Code:
mydomain = somedomain.com
myhostname = mail.somedomain.com
mydestination = $myhostname, localhost.$mydomain,mail.$mydomain,$mydomain
mynetworks = 212.18.32.32/27 127.0.0.0/8
relay_domains = $mydestination
smtpd_recipient_restrictions = permit_mynetworks,check_relay_domains
post the output of
postconf -n for further assistance.