No. We have configured the filter such that only the worst sorts of spam are "blocked" and deleted at the filter. All other questionable email is "quarantined" for your review. No legitimate email should be blocked. The real question is whether there is good email being quarantined. By default, you will receive one notification a day if there is any spam mail that was blocked. You may change this to a weekly notification (or turn it off altogether). When you visit the filter's web page, you may see some good email quarantined. If you do, check the box in front of the message and press the "Not Spam" button (as described above), this will help train the system. Then, press the "Deliver" button and the email will be delivered to your inbox.