Enroll button not working correctly in CoursePress

If a visitor clicks the"Sign-up" button on the course page, the pop-up seems to function correctly.

If a logged in user clicks the "Enroll" button on the course page, the pop-up give a confirmation that they are enrolled and the correct link.

However, if the course is a paid course, all I am getting is a pop-up with a blank screen.

I have Membership 2 installed, so I tried enabling and disabling protection, activating and deactivating the plugin - still didn't seem to work. I also tried to create an individual page with the shortcode [cp_pages page="enrollment_process"] instead of the virtual page as it says on the settings page and then changing the enrollment page to that page - still no go.

Am I missing something? I have enabled support access if anyone needs to check.