What should I check when ShipStation rejects several unrelated orders?

Check the shared store, building, and carrier configuration first when several unrelated orders fail together.

“ShipStation rejected order: no orderId returned” means the response lacked the ID Endless needs to confirm creation and did not provide a more specific reason. Check ShipStation before retrying because the response alone does not establish whether an order exists there.

1. Try Fetch Stores and the available carrier, service, and warehouse actions. Successful responses help confirm the connection works.
2. Compare the integration’s default store with the order’s sales-channel mapping. The mapping overrides the default. Use a store that accepts API-created orders, such as a manual-order store; a utility store appearing in Fetch Stores does not prove it accepts orders.
3. Confirm the building maps to the intended ShipStation warehouse.
4. Check carrier and service mappings. For UPS, FedEx, and DHL, the owned-carrier setting selects your own account when enabled and the walleted account otherwise. Enabling both settings does not select two accounts.
5. Search ShipStation for the Endless fulfillment order number before resending.
6. Check the destination address and service requirements.

For international failures, verify that the service supports the destination, the carrier account matches, and the country, postal code, province or state, and phone are suitable. Add any required customs details in ShipStation.

If removing a sales-channel store override resolves the problem, leave it unmapped to use the default or map it to a compatible store. Review the Timeline for the actual error. See other order failures and duplicate handling.