Wechat official account payment, reported that the payment signature verification failed, Wechat's online signature verification was passed. Is it a front-end error or a background interface error?

$.ajax ({

)

type:"post",
url:url_path+"/pay/weixinprepaid.json",
data:dataArray2,
async:false,
dataType:"json",

success:function(data){
    //
    var param = data.resInfo;
    var timeStamp = param.timeStamp.toString();
    var prepayid = "prepay_id="+param.prepayid;
    var noncestr = param.noncestr;
    var sign = param.sign;
    var signType = "MD5";
    var appid = param.appid;
        WeixinJSBridge.invoke(
        "getBrandWCPayRequest", {
                "appId":appid,               //     
                "timeStamp":timeStamp,       //1970     
                "nonceStr":noncestr,         //     
                "package":prepayid,     
                "signType":signType,         //:     
                "paySign":sign               // 
        },
        function(res){
            if(res.err_msg == "get_brand_wcpay_request:ok" ) {
              window.location.href="http://taxicustomer.nbzhidun.com/pages2/personal/balance.html"
            }else{
                                                           
            }
        }
);

},
error:function (xml) {

console.log(xml)
}

});

this is the code for my front end to call up the payment

msg: "success"
resInfo:

appid:"wx3169069333bfc3a1"
noncestr:"2dg8tz56eggjs6h9b4ck186c723alvag"
package:"Sign=WXPay"
partnerid:"1499166342"
prepayid:"wx30090614962920174c62b2ff3662300490"
sign:"15F4E62938A8F852D264592F7634B56E"
timestamp:1527642375

stateCode:0

this is the data returned by the background API