WP Smush Pro stops media library loading

Hi team

Been working on a site at http://www.smitewebdesign.co.nz/baytours and I couldn't get the media library to load. It was just a spinning circle.

I network deactivated the WP Smush Pro plugin and it worked again fine.

Any thoughts to what is causing it? I am using The Fox theme from Themeforest if that helps?