This error indicates there was a problem with the file being sent to Turnitin.
This is normally a temporary issue that can be resolved by Module Staff (see "If you are a member of staff" below).
If you are a student
You should contact your course staff in the first instance.
Your submission has been uploaded to Myplace and is available for the staff to review and grade. It is just the Turnitin aspect that will not be available.
If you are a member of staff
You can see the details of any Turnitin Error by hovering your cursor over the red X icon.
You can re-submit the student's content by clicking on the icon:
The Turnitin status should change from the error message to "Resubmitting", then "Turnitin status: Pending", then "Turnitin status: Queued" before finally (if successful) displaying a Turnitin ID.