Spamassassin running but not scanning messages

[santosh_n]

Hi,
I have Plesk 8.3 with spamassassin 3.1.7. When I check in the Plesk control I find that the spamassassin service is running. Also if I run "ps aux" I see lot of spamc processes like the following:

popuser 10647 0.0 0.0 4748 736 ? S 15:59 0:00 /usr/bin/spamc -s 256000 -u user@domainname.com -U /tmp/spamd_full.sock -E

(where 'user@domainname.com' is the actual email address)

However when I examine the message headers of such email I find that there are no X-Spam header lines. And a lot of spam is just getting through without being filtered.

Can anyone help troubleshoot this issue?

Thanks,
Santosh