Please update all required plugins – https://xstore.helpscoutdocs.com/article/37-plugins-update and temporary disable all 3rd party plugin. Then clear cache and check page loading.
Don’t keep enabled all the plugins that come bundled with XStore theme. Read about required and recommended plugins https://xstore.helpscoutdocs.com/article/36-included-plugins , check what recommended plugins you really plan to use depending on options that plugins offer and then enable them. Because every additional plugin slows down a site a little bit and there is no need to keep it enabled if you don’t use its options.