Select **Enable** next to the **Cutoff Date**. This is the last assignment **due date**.
If you wish to allow late work (a late penalty can be optionally deducted, if you scroll down on the Settings page), make sure that there is time between the close and cutoff dates (a minimum of 10 minutes is suggested, no upper limit).
If you don't want to allow late work, set the cutoff date to match the close date.