Turnitin gives the error message of "Turnitin assignment could not be created. date_post - post date must be after start date" when the assignment is opened by the teacher and "There was an issue accessing this assignment, please contact your instructor for more information" when the assignment is opened by the student.
Work Around
This seems to be caused by some error with availability start dates. If the availability start date is removed from the setting, the error no longer appears. If the instructor wishes to restrict student access until a certain date, they can do so in the Turnitin settings.
Cause
Unknown. Linked to availability start date.
Status
Not able to reproduce reliably. Looking for cause