报错：Object {errCode: -1000, errMsg: "joinVoIPChat:fail: -10088, -10, join room failed. errType: 4, errCode: -12020, errMsg: invalid signature, -1"}

语音能力已开通，实在不理解问题出在哪了，麻烦官方帮忙看看

//后端签名
var str = [appId, groupId, nonceStr, timeStamp].sort().join('')
var hash = CryptoJS.HmacSHA256(str, session_key)
signature = CryptoJS.enc.Hex.stringify(hash)
var data = { Signature: signature, NonceStr: room.NonceStr, TimeStamp: room.TimeStamp, GroupId: room.GroupId }


//前端调用
wx.joinVoIPChat({
        roomType:"voice",
        signature:data.Signature,
        nonceStr:data.NonceStr,
        timeStamp:data.TimeStamp,
        groupId:data.GroupId,
        success(res){
            console.log("加入语音房间成功",res)
            Tool.OpenRecord()
        },
        fail(err){
            console.log("加入语音房间失败",err)
        }
    })