请求：https://api.mch.weixin.qq.com/pay/combinedorder 报文： <xml>   <nonce_str><![CDATA[f0a062374ca348b6bdf0f56e024c746b]]></nonce_str>   <combine_appid><![CDATA[保密]]></combine_appid>   <combine_openid><![CDATA[保密]]></combine_openid>   <time_start>20170703172443</time_start>   <sign><![CDATA[3F8BAB634A8B2249CFC1E936C46D052F]]></sign>   <combine_out_trade_no>170703172443276</combine_out_trade_no>   <trade_type><![CDATA[JSAPI]]></trade_type>   <sub_order_list><![CDATA[{"order_num":2,"order_list":[{"out_trade_no":"170703172443276","appid":"保密","total_fee":1,"fee_type":"CNY","body":"test","mch_id":"保密"},{"out_trade_no":"170703172443276","appid":"保密 ","total_fee":2,"fee_type":"CNY","body":"test","mch_id":"保密"}]}]]></sub_order_list>  notify_url>https://wx.grgyintong.com/trip-wechat-web/wechat/pay/wx_notify]]>/notify_url>   <spbill_create_ip><![CDATA[10.2.152.138]]></spbill_create_ip>   <combine_mch_id>保密</combine_mch_id> </xml> 返回错误报文 {err_code=NOAUTH, return_msg=System Error, err_code_des=permission denied., return_code=FAIL} 查返回码说是：商户无此接口权限 但是调unifiedorder是可以的 但是调combinedorder却说商户无此接口权限 有人知道是为什么吗？是要到商户上哪个地方申请什么呢？