With PerfectMail, whitelisting takes precidence over blacklisting. Search the Mail Log (E-mail => Mail Log) for the message and check at the Scores (expand the Scores by clicking on the [+]) to see if the message was whitelisted.

If it was not whitelisted then check the Headers (expand the Headers by clicking on the [+]). The Envelope section of the Headers will show the relayhost, relayhostname, and env-from (envelope from address); make sure none of these entries are not whitelisted on your server.