451 4.3.5 Server Configuration Error - Can no longer receive outside emails

[kilburn]

Postfix is unable to contact postgrey. Make sure that it is running (/etc/init.d/postgrey start). Once it is, check the port where it's listening for incoming messages:

Code:

# netstat -tlnp

Then, change the port (last number) in "check_policy_service inet:127.0.0.1:60000":

Code:

smtpd_recipient_restrictions = reject_non_fqdn_recipient,
reject_unknown_recipient_domain,
permit_mynetworks,
permit_sasl_authenticated,
reject_unauth_destination,
reject_unlisted_recipient,
check_policy_service inet:127.0.0.1:12525,
check_policy_service inet:127.0.0.1:XXXXX,
permit

Finally, restart postfix so it loads the new configuration. This will solve your "Configuration error" problems, but not the "User not found...". Are you sure that the addresses that throw this error are correctly created? Check their status in the mail address list inside the panel...