Support System shortcode isn't working correctly

I'm having troubles with the Support System plugin with the Customize My Account Page plugin from Yith. (https://yithemes.com/themes/plugins/yith-woocommerce-customize-myaccount-page/)

When I create an endpoint to show a tab and place there the shortcode to see the Support Page ([support-system-tickets-index]) I get an blank section. On the selected page (set in the settings of the Support System Plugin) everythings shows correctly.