Course Signup Checkout not working

Setup course at and set price.
Clicking on Signup and registering redirects to Cart. Cart has checkout button, but it reloads cart.
Need help getting checkout to work.

Searched for this issue, didn't find it.
Tried the Getting Support Flowchart under The Good Support Ticket page. Disabled all plugins except MarketPress and CoursePress. Still broken. Changed back to TwentySixteen Theme. Still broken.

Granted Support Access in the WPMU DEV Dashboard.

Ready for assistance.