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

Errors

Error code	Message
20	E020: "%s" Invalid Order Item ID
21	E021: OMS Api Error Occurred
23	E023: "%s" Invalid Order Item IDs
24	E024: "%s" Invalid Delivery Type
25	E025: "%s" Invalid Shipping Provider
29	E029: Order items must be from the same order
73	E073: All order items must have status Pending or Ready To Ship. (%s)
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
94	E094: Serial numbers specified incorrectly
95	E095: Invalid serial number format (%s)
96	E096: Duplicate serial number among order items (%s)
119	E119: Some order items are not yet ready to be processed, please try again later. (%s).