Locked Content/Assignments
Instructors may lock course content until a specific time or until you have completed previous assignment(s). If you can't access an assignment in your course, it could be because of one of these reasons.
Module Learning Path
Your instructor may be using Module Requirements/Prerequisites to create a learning path with content and assignments you read and complete in a certain order. If you find that you don't have access to an assignment, be sure to check that you have completed all the previous assignments, including viewing any pages that you may have missed. Be sure to select Modules from the sidebar, to see any non-assignment pages that you may be required to view.
Availability Dates
Assignments with upcoming due dates appear in the “Assignments” menu at the top of your Canvas page. It is possible that you don’t yet have access to these assignments because of the availability date set by your instructor.
Your instructor may also lock entire Modules (or sets of assignments) until a specified date. If your instructor is using Modules in your course, locked items will appear in the list with grey text that you can't click.