【物流助手】即时配送，闪送预下单为什么返回错误码"1"？

即时配送对接的物流公司是闪送，预下单接口preAddOrder返回结果如下：

{
	"resultcode": 1,
	"resultmsg": "is_direct_delivery 设置应该为1,只能直拿直送",
	"fee": 0,
	"deliverfee": 0,
	"tips": 0,
	"insurancefee": 0,
	"distance": 0,
	"delivery_token": "",
	"dispatch_duration": 0
}

请求参数如下：

{
	"shop": {
		"goods_name": "宫崎骏龙猫伞双层晴雨伞礼品伞小香伞骷髅头伞狐狸头伞LED灯伞",
		"img_url": "https://aaa.aliyuncs.com/img/goods_logo/xxx.jpg",
		"wxa_path": "pages/public_order_detail/public_order_detail?order_id=205692243825262592",
		"goods_count": 1
	},
	"receiver": {
		"address_detail": "江苏省宿迁市宿豫区项王东路16号",
		"address": "江苏省宿迁市宿豫区项王东路16号",
		"lng": 118.324570000,
		"city": "宿迁市",
		"phone": 15751557639,
		"name": "胡某",
		"coordinate_type": 0,
		"lat": 33.941620000
	},
	"sub_biz_id": 1803,
	"sender": {
		"address_detail": "义乌商贸城十五街",
		"address": "江苏省宿迁市宿城区",
		"lng": 118.277906016,
		"city": "宿迁市",
		"phone": 18945900592,
		"name": "家居百货展示店铺",
		"coordinate_type": 0,
		"lat": 33.934423012
	},
	"openid": "o81Cv4og4j5IgiUAZ11dknq_67VY",
	"delivery_id": "SS",
	"shopid": "M20111499377",
	"delivery_sign": "67986d31b6a31c8a9f19c99c0ca4333f6b286829",
	"shop_order_id": "205692243825262592",
	"cargo": {
		"cargo_first_class": "日用百货",
		"goods_value": 3.00,
		"cargo_second_class": "办公家居用品",
		"goods_weight": 0.36
	},
	"order_info ": {
		"is_direct_delivery": 1,
		"delivery_service_code": "1",
		"is_finish_code_needed": 1,
		"is_pickup_code_needed": 1
	},
	"shop_no": "312849"
}

不明白的是，请求参数里加入了is_direct_delivery参数，并设置为1，为什么返回结果仍然提示“is_direct_delivery 设置应该为1”？