不知道哪里出错,发送数据包如下：

{ "combine_out_trade_no": "20220712200250", "combine_mchid": "1604977470",

"combine_appid": "wx2b708d2c7d3d90ab", "scene_info": { "device_id": "POS1:123",

"payer_client_ip": "183.6.118.97" }, "sub_orders":

[{"mchid":"1604977470","attach":"\u88d5\u4e30","amount":{"total_amount":1,"currency":"CNY"},"out_trade_no":"fengpan_220220711144334","description":"\u6fc0\u6d3b\u4fdd\u8bc1\u91d1"},{"mchid":"1604977470","attach":"\u88d5\u4e30","amount":{"total_amount":1,"currency":"CNY"},"out_trade_no":"fengpan_220220711144300","description":"\u6fc0\u6d3b\u4fdd\u8bc1\u91d1"}],

"combine_payer_info": { "openid": "oYSoxuP3Pbe093tGoInhuTYvVUY8" },

"time_start": 2022-07-13T20:02:50+08:00", "time_expire":

2022-07-13T20:12:50+08:00", "notify_url":

"https://erp.yfdc.net/pay/example/notify.php"

}{"code":"SYSTEM_ERROR","message":"系统繁忙，请稍后重试"}