Hello,
Could you, please, update PHP version at your site to 7.2 http://prntscr.com/s9l36b ? At this moment you use out of date version 5.6 http://prntscr.com/s9l2rp Let me know once you update PHP and we’ll be able to proceed with plugin update because the current version of your WooCommerce (3.1.2) is not compatible with the latest version of our theme.
Regards