When you add a Figma prototype to Ballpark, we not only embed the prototype itself, but we also extract all the elements from the design file to enable much of the click-tracking and heatmaps we generate.

That means that if the file that powers your prototype is made private, Ballpark can't 'see' your prototype.

The quickest way to solve this is by either changing the permission of your file to be public or copy and paste the frames that you need to a new personal file and make that public.