Why Isn't My Usual Carrier Available?
Amazon determines which partnered shipping services are available for each shipment.
Carrier availability can depend on shipment information and the options Amazon returns through its API.
Why Can Seller Central Look Different?
Amazon's Seller Central interface and its API do not always provide identical options.
This means a carrier or shipping option visible directly in Seller Central may not necessarily be available to AccelerList through Amazon's API.
What Can I Do?
First verify that your shipment information is complete, including:
Ship-from address
Box weight
Box dimensions
Shipment destination
Box content
If the partnered option still isn't available, you may need to use another shipping option returned by Amazon or review the shipment directly in Seller Central.