How to synchronize the shipment information of an order

[GermanDrop1]

We have a Shopify application and now we have a requirement to synchronize the logistics information of merchant orders to Shopify orders.According to the official interface document, the first interface to query the shipment order data of the order is:"admin/api/2023-10/assigned_fulfillment_orders.json";

After receiving the shipping order ID of the order, use the interface:

"/admin/api/2023-10/fulfillments.json"

Synchronize order shipment data.

But when I executed the first interface, the return value of the interface was:

"The api_client is not associated with any shipping services"

I would like to ask the technical team if my idea of synchronizing shipping information with the interface above is correct.How should we handle this return value situation? Can the official provide a code example in PHP language for synchronizing order shipping information? Thank you!