All submissions suddenly disappeared

Community Novice

Hi! I had an assignment due on 4/7 (although in Canvas, it says there's no due date) and all my students were able to upload their submissions and I even reviewed some of their assignments in SpeedGrader with my students on zoom although I haven't graded the assignment yet. But then on 4/22, when I finally decided to open that certain assignment that all of them already submitted in Speed Grader to grade it, all of their submissions were gone saying, "This student does not have a submission for this assignment." I don't remember whether I did something last 4/7.

Does anyone here know the cause of their disappearance or what I did wrong ? and how can I recover those missing submissions? Please help me! 

Users who also had this question