在请求官方【https://api.mch.weixin.qq.com/v3/combine-transactions/jsapi】合单下单-JS支付API，一直报400 Bad Request错误 我的header为：【metaJson为官方php提供SDK，传过去为了签名，所以这个应该没错，我用官方phpSDK进件和进件查询请求接口都正常了，到这个合单就包400错误，按跟进件的POST请求一样啊】 "Accept": "application/json", "Content-Type": "application/json", "Wechatpay-Serial": "5CFB23F5EFE777A2651C4FE409D9FD6A007FC0C3", "metaJson": "{\"combine_appid\":\"wx09f6dc683d4ab4d8\",\"combine_mchid\":\"1557374351\",\"combine_out_trade_no\":\"flq_1584957318\", \"scene_info\":{\"device_id\":\"XCX:1\",\"payer_client_ip\":\"121.207.122.155\"},\"sub_orders\":[{\"mchid\":\"1557374351\",\"attach\": \"599\",\"amount\":{\"total_amount\":10,\"currency\":\"CNY\"},\"out_trade_no\":\"fl12q_1584957318\",\"sub_mchid\":\"1581147271\", \"detail\":\"\",\"profit_sharing\":true,\"description\":\"\\u6811\\u8102\\u7ebd\\u626324L\"}],\"combine_payer_info\": {\"openid\":\"oRL0J41MdqQ1TfwoFf0goL2k1IPg\"},\"time_start\":\"2020-03-23T17:59:60+08:00\",\"time_expire\": \"2020-03-24T17:59:60+08:00\",\"notify_url\":\"https:\\/\\/api.fuliaoquan.com\\/\",\"limit_pay\":[\"no_debit\"]}" json为 {     "combine_appid": "wx09f6dXXXXd4ab4d8",     "combine_mchid": "15573***51",     "combine_out_trade_no": "f_1584956927",     "scene_info": {         "device_id": "XCX:1",         "payer_client_ip": "125.206.122.155"     },     "sub_orders": [         {             "mchid": "15573**351",             "attach": "599",             "amount": {                 "total_amount": 10,                 "currency": "CNY"             },             "out_trade_no": "f2_1584956927",             "sub_mchid": "1581**7271",             "detail": "",             "profit_sharing": true,             "description": "树脂纽扣24L"         }     ],     "combine_payer_info": {         "openid": "oRL0J41MdqQ1TfwoFf0goL2k1IPg"     },     "time_start": "2020-03-23T17:59:60+08:00",     "time_expire": "2020-03-24T17:59:60+08:00",     "notify_url": "https://api.XXX.com/",     "limit_pay": [         "no_debit"     ] } 按官方的JSON实例，没有必填的参数也填上去了，回调地址写的是一个官网，还没错回调，按理说现在回调地址不会请求校验把。 实在想不出哪里出问题了！还是参数错了。因为商户进件接口都是这样请求，都正常返回的！