The error "Turnitin assignment could not be created. date post - post date must be after start date" typically occurs when the Feedback Release Date is accidentally scheduled to occur before the assignment's official Start Date.
This conflict most frequently happens when an entire course, along with its previous deadlines, has been copied over from a past term or another instructor's shell.
Step-by-step resolution
To resolve this, you must reset and reapply the dates in a specific order:
- Open your LMS assignment settings, completely remove all assignment dates and save your changes.
- Next, access the Turnitin assignment settings, update the Feedback release date to the correct date, and save.
- Return to your main LMS assignment settings one last time. Re-enter your correct Available from (Start date) and Due date, then save.
Once saved, these corrected deadlines will automatically sync and copy over to the Turnitin assignment.