Create woocommerce order on new user registration

Question

The goal is to create a new order when a new user registers wordpress site. To achieve that, the following hook was added to child theme's functions.php.

add_action( 'user_register', 'add_order', 10, 1 );

    function add_order( $user_id ) {

        $order = wc_create_order();
        $order->set_customer_id($user_id);
        $order->save();
    }

However, when a new user registers, no new order is created. No error is seen in the log. Wondering how to achieve the goal correctly.