Page does not display?

Hi

I’m currently migrating a site from Joomla to WordPress and I’m looking at using WP Download Manager to replace DOCman. I’ve installed WP Download Manager however I think there might be an incompatibility with the theme I’m using from Rocketthemes (https://www.rockettheme.com/wordpress/themes/callisto)

On this page I can see my downloads listed – https://test.airleague.com.au/download-category/downloads/

however when I go to the document page (https://test.airleague.com.au/download/nsw-boys-group-review-digest-2017/) I just get a white screen. No error etc.

I’ve tried switching to the Twenty Sixteen theme and the page is visible. Really odd. Help and suggestions appreciated.

Regards,
Brian

The page I need help with: [log in to see the link]