[CoursePress Pro] CoursePress Pro pages not working

Hi WPMUDEV,
I run a multisite with CoursePress Pro. I can create courses but a few of the pages are not working, they are just blank. No errors in the console. It's about:
/courses/coursename/notifications
/courses/coursename/discussion

I enabled discussions in the course and comments in the Wordpress settings but both pages are blank.

Can you help me? Thanks,
- Menno