Sender Access Restrictions and MySQL Table

[Asai]

Greetings,

I'm using Postfix with MySQL, and am trying to restrict certain users to 
send and receive from my network only.  I have had marginal success with 
this using a MySQL query.

In the MySQL table, these users have 'local_only' in the smtp_access 
column, all other users have 'Y' in this column. In 
/smtpd_sender_restrictions /I have added /check_sender_access 
mysql:/etc/postfix/mysql_restricted_senders.cf /which queries the user 
and returns either 'Y' or 'local_only'.  Then I have specified 
/smtpd_restriction_classes = local_only /AND
/local_only = check_sender_access 
mysql:/etc/postfix/mysql_local_domains.cf, reject /

This works for the restricted users.  However, it ends up blocking all 
other non-restricted users with a 'misconfigured server' error.  What am 
I missing?