404. That’s an error.
The requested URL /shop/index.php/catalog/product_compare/add/product/55641/uenc/aHR0cDovL3RlY2hub2ZveC5kZS9zaG9wL2luZGV4LnBocC9sbmIvcXVhZC1sbmIuaHRtbA,,/form_key/3HfOJ6VHJzF2uDjZ/
was not found on this server. That’s all we know.