Make sure that you opened up the correct ports on the Plesk firewall. The network tests will not work if the ports are not properly opened.
Specify which locales are considered OK for incoming mail. Mail using the character sets that are allowed by this option will not be marked as possibly being spam in a foreign language. If you receive lots of spam in foreign languages, and never get any non-spam in these languages, this may help.
Warden -> Settings -> Anti-spam Settings.
Warden -> Settings -> Network Settings.
DCC is not installed by default because it is not open source but is still highly recommended. We recommend that you install and setup DCC so that you can use it:
By default Plesk only scans emails smaller than 256K in size. We recommend raising this limit.
Edit the file
/etc/psa/psa.conf and raise the limit to something more reasonable like 768K
# SpamAssassin max mail size (in bytes) SA_MAX_MAIL_SIZE 768000
Then restart spamassassin:
service spamassassin restart
If this is the first time running SpamAssassin and you want to enable spam filtering for all mailboxes on the server then run the following command:
for i in `mysql -uadmin -p\`cat /etc/psa/.psa.shadow\` psa -Ns -e "select concat(mail.mail_name,\"@\",domains.name) as address from mail,domains,accounts where mail.dom_id=domains.id and mail.account_id=accounts.id order by address"`; do /usr/local/psa/bin/spamassassin -u $i -status true ; done