1. Rough Draft- Saving in Private Mode
A student has the ability to save their Response to Assignment, yet not submit it to the instructor. When the Saved button is selected, the Save Changes window gives them the opportunity to save it to private (as a rough draft) or to instructor (as a submission of an assignment). When it is saved as private, the instructor cannot view the response. The simple solution is to tell your student to re-save their response, but to save it to the Instructor.
This 2 minute video demonstrates this simple solution.
2. Composition vs. Respond to Assignment
Another reason you might not be able to see your student response is because rather than Responding to the Assignment, they have accidentally Created a Composition. This is very easy to resolve. The following video demonstrates this simple mistake and it's easy solution.