Why won't my gradebook automatically mark assignments as late/missing?

Gradebook late and missing assignment settings will automatically apply deductions for most late or missing assignments. For information about how to adjust these settings, see here.

If your late and missing assignment settings are correct but Canvas doesn't apply an automatic deduction after the assignment due date, this may be because the submission type is "No Submission" or "On Paper." Canvas notes here that "The Late Submission policy will not be automatically applied to No Submission or On Paper assignments." This is also true for missing assignment settings.

In other words, Canvas doesn't know that nothing has been submitted yet, because for this assignment nothing will be submitted within Canvas. In this case, you'll need to manually mark the assignment as late or missing.