Hello, @Santiago,
I have debugged your site and find that the issue you are facing is because of the plugins, you are using the other theme as well on your site and that one has some plugins as well and you have also some extra third-party plugins as well.
So first of all, please deactivate all the plugins from your site and then Activate the XStore theme from Appearance >> Themes.
And after that, you have to Install or Activate the theme-required plugins only and check back to your site after clearing the browser cache.
Hope it will solve your issue, and then you can activate all of your third party plugins again one by one and check which one is conflicting and creating the issue on your site.
Regards 8Themes Team.