Double deserialization in client

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C#

JSON

I am serializing objects in cloud server in the web role:

using Newtonsoft.Json;    
string returnJsonMessage = JsonConvert.SerializeObject(returnMessage);

On the client side:

BaseResponseDeviceMessage retVal = null;
var req = HttpWebRequest.Create(@reqString);
req.Method = requestMethod;
req.ContentLength = 0;
req.ContentType = @"application/json";

string jsonResp = "";
try
{
    HttpWebResponse resp = (HttpWebResponse)req.GetResponse();
    using (StreamReader sr = new StreamReader(resp.GetResponseStream()))
    {
        jsonResp = sr.ReadToEnd();
    }

    string t = JsonConvert.DeserializeObject<string>(jsonResp);
    retVal = JsonConvert.DeserializeObject<T>(t);

}

You can see that in order to get my message back, I need to DeSerialize twice. Why? how can this problem be solved? Thank you all, and a good day.