If you upgraded to 2.3.0 from a previous release, you will be missing a database column.
This applies only if you ran the 2.3.0 installer/upgrader package. This was fixed for 2.3.1 and subsequent releases.
2.3.0 was a preview release and not generally available.
To fix the issue run the below.
mysql -u openaudit -popenauditpassword openaudit -e "ALTER TABLE queue ADD pid int(10) unsigned NOT NULL DEFAULT '0' AFTER type;"