Hi,
The URL of your checkout menu item is not
restaurantdirect.ca/index.php/restaurants
It's
restaurantdirect.ca/checkout-user
However, if you access that menu item without any products in the cart, you'll be redirected to the URL you specified in the "URL where you will be redirected when the cart is empty" setting of the HikaShop configuration.
So I supposed that you entered in here the text "restaurants". However, that is not a valid URL of your website and that's why you end up with a 404 error.
So please check that setting and either leave that field empty or change it to a valid URL.