StreaMex,
You need to add a return or newline at the end of your code.
here is an example of my code:
string get_menu_request = "{\"id\":0,\"jsonrpc\":\"2.0\",\"method\":\"miner_getstat1\",\"psw\":\"" + _password + "\"}" + Environment.NewLine;
NetworkStream serverStream = clientSocket.GetStream();
byte[] outStream = System.Text.Encoding.ASCII.GetBytes(get_menu_request);
serverStream.Write(outStream, 0, outStream.Length);
serverStream.Flush();