The customer is returned to the checkout page or the confirm order page and shown the error message when the store is setup to use a real-time shipping rate service provider.
The order cannot be processed. The shipping rate service did not provide rates because of a problem and no other shipping is available to the address you provided. Please return to checkout and try again or contact the store administrator.
This error occurs when no shipping methods were setup to cover the shipping address provided by the customer when a real-time shipping rate system is enabled. When a real-time shipping rate service such as FedEx, UPS, USPS, CanadaPost or AusPost is setup but fails (for whatever reason) to return rates and no other fallback rates or regular calculated shipping rate settings apply to the order, the order validation process will prevent the order from being processed.
For example, Shopp is setup to serve the USA and Canada in the Target Markets setting under Shopp → Setup and a shipping calculator is setup with rates for Canada but not USA. Additionally, FedEx is configured to provide real-time shipping rates for customers in all the target markets. During checkout, a customer provides a USA shipping address when a connection problem with FedEx occurs. This will cause the shipping costs to display as Not Available in the cart and checkout pages. Further, the final order validation process in Shopp is designed to prevent orders from proceeding for orders with shipped products that have no shipping methods that apply. Due to the failure of the real-time shipping rate provider to return rates, and no other valid shipping methods applying to the USA destination, the order validation process will fail and the customer is returned to checkout with the error.
It should be noted that having no shipping costs apply is different than an order with $0 shipping costs. Setting up a shipping method that applies $0 shipping costs to a destination will satisfy the requirements of the order validation system.
When setting up a real-time shipping rate system, it is strongly recommended that you also setup a shipping calculator with the Real-time rates fallback setting enabled. The most effective solution is to setup a catch-all fallback shipping method that includes a shipping rate (which could be $0) for All Markets. This ensures that at a minimum, a valid shipping method is available to serve all the Target Markets enabled for the shop.
Alternatively, several fallback shipping methods or other shipping methods that are not set as fallbacks can be setup with destinations that cover all of the enabled Target Markets individually. This is more time consuming to setup, but also provides more control over shipping costs for specific destinations.