The Moodle cron process is a PHP script that must run regularly in the background and that runs different scheduled tasks at regular intervals. For Turnitin specifically, there is a cronjob that is responsible for pushing submissions from Moodle through to Turnitin.
If submissions within a Moodle Plagiarism Plugin assignment are showing a QUEUED status, this indicates that the cron has either:
-
Not yet ran
-
Stopped working
-
Been blocked by something on the server
To resolve this, the Moodle administrator will need to test Turnitin connectivity and check the cron settings: Site administration Plugins > Plagiarism Turnitin Plagiarism plugin Test Turnitin Connection link.
If the connection to Turnitin has failed, the Moodle administrator will need to ensure that the cron is configured. The following link allows you to select your Moodle version, describes the Moodle cron, and also gives information on configuring it: https://docs.moodle.org/39/en/Cron
Note: It is not known if there is a default cronjob frequency setting, however, it should be dependent on the size of the system it's running on.