Courses don't appear in Hustle "Page" selector field

Hi Gurus,

How do I use Hustle Popups and slide-ins on CoursePress Pro Course pages?
For example, I want a popup to appear on this page: http://growing.ecoevolver.com/courses/grow-food-indoors-course-stream/

However, that Page never appears in the selection box outlined in the attached image.

Am I missing something here?

Thanks kindly,