\"errcode\":47001,\"errmsg\":\"data format error hint: [eRgjqa0035b464]\"} 我的后台是C#的 请帮我看看，我这个data format 是指传参数的格式，还是什么格式不对啊

string url = "https://api.weixin.qq.com/wxa/msg_sec_check?access_token="
                + JsCode2Session();
            JObject jsonObject = new JObject();
            jsonObject.Add("content", msg);
            string content = jsonObject.ToString();
            string str = HttpHelper.doHttpPost(url, content);

            JObject jobj = JObject.Parse(str);