"code": 29009, "message": "Purchase order cannot be created for a non-purchase item."

Question

https://www.zohoapis.com/inventory/v1/purchaseorders?organization_id=######

{
    "purchaseorder_number": "BBBBBBA",
    "date": "2015-05-28",
    "vendor_id": 3125431000005946221,
    "line_items": [
        {
            "SKU": "BDC9999978",
            "name":"One Playa Del Carmen"
        //   "item_id": 3125431000002004431
           
        }
    ]


}

I can add with "SKU" I find this problem :

 "code": 29009,
    "message": "Purchase order cannot be created for a non-purchase item."