请求数据如下，一直返回return_msg=System Error, return_code=FAIL，没别的错误说明，

<?xml version="1.0" encoding="UTF-8" standalone="no"?>

<xml>

<time_expire>20191212090554</time_expire>

<nonce_str>x5xN6HzcrtBTGThUkgapgNpXSHmZ2GC5</nonce_str>

<combine_appid>wxafb2df76dd468b91</combine_appid>

<time_start>20191211090554</time_start>

<sign>4F1BFEA7D05CF58BAD7B116B77E98ED450B54F1CD9E590F8E6147E4091AB27A4</sign>

http://111.115.51.74:8086/eshop/wx/notify

<spbill_create_ip>111.115.51.74</spbill_create_ip>

<device_info>test</device_info>

<combine_openid>oJJ--4r_TBCePl0q6bmES08rYsw4</combine_openid>

<combine_out_trade_no>Xnszi3ODssuxv5orUIeNK3FOjHl9MVnG</combine_out_trade_no>

<trade_type>JSAPI</trade_type>

<sub_order_list>{"order_list":[{"appid":"wxafb2df76dd468b91","attach":"test","body":"test-零售","fee_type":"CNY","mch_id":"1561080281","out_trade_no":"zuwT6u8Mon0qsZVqW2HO7ivYeeAjZPRQ","sub_mch_id":"1561080281","total_fee":10},{"appid":"wxafb2df76dd468b91","attach":"test","body":"test-租赁","fee_type":"CNY","mch_id":"1561080281","out_trade_no":"PXiHK61zaj5W4ty618smMu6VTm71LGHD","sub_mch_id":"1561080281","total_fee":10}],"order_num":2}</sub_order_list>

<sign_type>HMAC-SHA256</sign_type>

<combine_mch_id>1561080281</combine_mch_id>

</xml>