Coursepress Hanging on enrol button click


I am attempting to setup a test course and enrol to it as a test of the click flow and payment process.

When I am logged in and click on enrol for the course, the program seems to hang with no feedback and I am presented with a blank popup window and cannot continue any further.

This problem appears to persist through update to the latest version of the plugin.

Can you advise on where to look? Perhaps I have not done enough to setup the test course?