【已解决】钉钉注册通讯录接口错误：返回文本非success

这两天在调用钉钉注册通讯录事件回调接口（ [font=&]https://oapi.dingtalk.com/call_back/register_call_back?access_token=ACCESS_TOKEN）的时候遇到错误：返回文本非success
查阅了网上的文档，很多人遇到此问题，有个别人解决了，但是没有说的很明白怎么解决的，最后自己摸索，终于调通了！所以记录下来，为大家节约时间！


我使用的是.NET WebAPI 实现的回调，下面直接贴代码（ 重点看 下面 写 注意的地方）
         //注意：返回类型是 dynamic  ，而不是string
        public dynamic Post([FromBody]ContactEncryptRequest contactEncrypt, [FromUri] ContactRequest contact)
        {
            string token = "112121212121211";//自定义随机串
            string aes_key = "b1234567890123456789012345678901234567890ac";//自定义随机串43位
            string suiteKey = "ding**********************";//CorpID

            var dingTalkCrypt = new DingTalkCrypt(token, aes_key, suiteKey);
            string plainText = "";
            dingTalkCrypt.DecryptMsg(contact.Signature, contact.Timestamp, contact.Nonce, contactEncrypt.Encrypt, ref plainText);

            var plain = JsonConvert.DeserializeObject<dynamic>(plainText);
            if (plain.EventType == "check_url")
            {
                //------------加密数据返回-----------------------
                string signature = "";
                string encrypt = "";
                try
                {
                    dingTalkCrypt = new DingTalkCrypt(token, aes_key, suiteKey);
                    //注意：此处的 Timestamp和 Nonce是从回调接收到的
                    dingTalkCrypt.EncryptMsg("success",  contact.Timestamp, contact.Nonce,  ref encrypt, ref signature);
                }
                catch (Exception ex)
                {
                    LoggingFactory.GetLogger().Error("加密返回数据：" + ex.Message);
                }
                //注意：此处的 Timestamp和 Nonce也是从回调接收到的
                Hashtable jsonMap = new Hashtable
                {
                    {"msg_signature", signature},
                    {"timeStamp",  contact.Timestamp },
                    {"nonce",  contact.Nonce },
                    {"encrypt", encrypt}
                };
                //特别注意：不要转换为json string 类型返回，直接 返回Json对象
                //string result = JsonConvert.SerializeObject(jsonMap);
                return jsonMap;
            }
            else
            {
                return null;
            }
        }
  
  上面的代码测试通过的，如有疑问，请回复！！！或者 QQ 812410472