Hello,
Your site under maintenance mode, so I can’t check it.
Looks like XStore Core plugin is deactivated on your site or version of this plugin is not suitable to the theme version. Please check our changelog – https://xstore.8theme.com/update-history/ http://prntscr.com/poqc7m http://prntscr.com/poqcb2
https://xstore.helpscoutdocs.com/article/63-theme-update
https://xstore.helpscoutdocs.com/article/37-plugins-update
Here you can find a list of required plugins – https://xstore.helpscoutdocs.com/article/36-included-plugins
Regards