Hello,
Your browser console indicate that you have some JS errors in the page.
Because of these errors, the code of "notify.js" is not process at it should so it does not return the information that it display a notification (because it do not display it) so the redirection is made as a fallback since there is no plugin to handle the add to cart event.
So you can see to fix your errors regarding mobileCheck and jQuery ; or you can perform a view override of the "product / cart" view to replace
o.removeClass(el, "hikashop_checkout_loading");
});
});
</script>
By
o.removeClass(el, "hikashop_checkout_loading");
});
return true;
});
</script>
So the HikaShop cart module will block the redirection to the checkout (which is not a good and viable solution but at least the JS errors you have would not impact that code).
Regards,