This document explains the meaning of the "Class is closed and wait list is full" error message and how it can be resolved.
What it means:The department offering the class has limited the number of students who can be on this class’s wait list. That list is now full.
What to do:Since you can’t add yourself to the wait list now, check back from time to time to see if spots on the wait list open up.
Or, contact the department offering the class, as they manage the wait list. Although departments don’t generally share information like how long the wait list is, some may adjust the number of available seats (or wait list size) in high-demand classes.