调用的是V3 接口  ： https://api.mch.weixin.qq.com/v3/combine-transactions/jsapi

body 参数为： {"combine_appid":"wx0bc4ed9b17a3f00c","combine_mchid":"1612453565","combine_out_trade_no":"rhggl47k51n8kiafc6j8fmr5johy6j7z","combine_payer_info":{"openid":"o-jOJ5EAw_o4hOUe7tNYvsIAqTwU"},"notify_url":"http://3728ad8422.zicp.vip/trade_api/order/pay/pay_result_callback_h5","sub_orders":[{"amount":{"currency":"CNY","total_amount":10},"attach":"1336","description":"毛茸茸玩具","mchid":"1520389741","out_trade_no":"4564461461"},{"amount":{"currency":"CNY","total_amount":10},"attach":"1336","description":"毛茸茸玩具","mchid":"1612453565","out_trade_no":"54641246563","sub_mchid":"1613929669"}]}

sign 签名为： mchid="1612453565",nonce_str="y2223123121321321g",timestamp="1631762234",serial_no="70500e28e986054d23a17bca544b267ad97fa3ea",signature="jym8B+gM09c4T7jGqge69tBcqskYIA5qnhaPbP77mCcEZv/dvk9WJ2y2hCpV054DpTcTEmf+umtajKBwBU3ClYUIRMNPphm41ckxd/HvxMdysQX1Gh/kQvNN2eqljh1S6ReqOeeIcmmoUeWoU7Up+LBSL8vYa+jzljVx6H/Sj3t6NkVY0hXGyff8/WzvrBLviPPakDCPbFmTHthI1HKIFfB00r0qEo6ebv+Leh9WjSuWI1WHiR05Htdtp+24P2sxi9mmqJF8Kubb6g6JJjRhCrb2oLeMEvMrNlOAFYvR3uNPnb3fJuX+niOOnDnrPMyTPvTO+LopQS88Om3kLj1+fw=="

步骤都是按照微信V3 api 的签名步骤来的， 现在报错排查不到报错的原因