When using Quest, you may need to manually request enrollment to gain access to a course. In the "Unique #" field enter the unique number for the course you are requesting enrollment in, this is not the same as the title of the course. Your instructor should be able to provide the unique for you, if you can't find it in the course listings or other information provided by your school.
This will bring up a list of courses using that unique number; make sure you select the correct course as some courses share unique numbers. Once you are done select "Request enrollment".
After you submit your request you will have to wait for your instructor to approve it. Once approved, your courses will be listed on your homepage.