At times we may have trouble locating an assignment in the gradebook. Or even via the assignments tab. More than likely, assignment either does NOT have a due date or it does but is contained in another grading period. To find your assignment; choose the proper grading period to locate:
Same as in the default gradebook view; be sure "all grading periods" are selected via the assignments tab as well!
If an assignment is in the wrong grading period; Change due date to fit within intended range of dates for grading period of choice!