- In Warden under Settings -> Anti-spam Milter Settings -> make sure that "Scan outgoing Non-SMTP" is checked.
- In each of your php.ini settings make sure that "mail.add_x_header" is set to On.
Example: To enable the X-PHP-Originating-Script header for PHP 7.0 so that it can be used by Warden.
Edit the file /opt/plesk/php/7.0/etc/php.ini
; Add X-PHP-Originating-Script: that will include uid of the script followed by the filename mail.add_x_header = On
Restart the PHP 7.0 FPM handler:
service plesk-php70-fpm.service restart
Repeat the procedure for every version of PHP that you want Warden to track.