The API responds by sending purchase order details in the response:


PurchaseOrderId	Unsigned	Seller Center identification
PurchaseOrderNumber	String	Order number in Seller Center

Errors

Error code	Message	Explanation
20	E020: "%s" Invalid Order Item ID
21	E021: OMS Api Error Occurred
23	E023: "%s" Invalid Order Item IDs
25	E025: "%s" Invalid Shipping Provider
26	E026: "%s" Invalid Tracking Number
29	E029: Order items must be from the same order
31	E031: Tracking ID incorrect. Example tracking ID: "%s"
73	E073: All order items must have status Pending or Ready To Ship. (%s)
63	E063: The tracking code %s has already been used
91	E091: You are not allowed to set the shipment provider and tracking number and the delivery type is wrong. Please use send_to_warehouse
119	E119: Some order items are not yet ready to be processed, please try again later. (%s).	One or more order items are not fully handled by Seller Center, so they cannot be processed yet.
121	E121: Invalid Packing ID