I created a delivery profile, but customers can't select any shipping rate. Why is this happening?

When calculating the shipping cost for subscription rules covered by the delivery profile, Shopify won't use any of your standard shipping rates set up in your shop. This means that if you set up conditions (min and max price or weight) when these rates can be used, make sure to also set up default rate for orders that don't conform your current conditions, otherwise these customers won't be able to place an order in your shop.