Appointments+ and Marketpress - Buy Now Button Not Working

Link:
https://jannus.org/store/products/appointment-2

I created this appointment "product" from the appointment plugin by checking the integrate with Marketpress checkbox and the "Create and Appointment Product Page" checkbox. The Buy Now button only refreshes the page, it does not bring the user into the process of making the purchase.

I have already set up the sandbox for an authorize.net account and am able to set up a normal product just fine. This integration does not seem to work however.