WebRequest send always null

[rocamarian9]

Hi I'm trying to test WebRequest in mql5 but every time I send a message to the server, it receive just {} with no data in

//+------------------------------------------------------------------+
//|                                                         Test.mq5 |
//|                        Copyright 2020, MetaQuotes Software Corp. |
//|                                             https://www.mql5.com |
//+------------------------------------------------------------------+
#property copyright "Copyright 2020, MetaQuotes Software Corp."
#property link      "https://www.mql5.com"
#property version   "1.00"
//+------------------------------------------------------------------+
//| Expert initialization function                                   |
//+------------------------------------------------------------------+
int OnInit()
  {
//---
   SendTest("ciao");
//---
   return(INIT_SUCCEEDED);
  }
//+------------------------------------------------------------------+
//| Expert deinitialization function                                 |
//+------------------------------------------------------------------+
void OnDeinit(const int reason)
  {
//---
   
  }
//+------------------------------------------------------------------+
//| Expert tick function                                             |
//+------------------------------------------------------------------+
void OnTick()
  {
//---
   
  }
//+------------------------------------------------------------------+

void SendTest(string mex){
                 string headers;
       char post[],rawResult[];
       string toSend = mex;
       StringToCharArray(toSend,post);
       string url = "http://localhost/medie";
       int res;
       res = WebRequest("GET",url,NULL, NULL, 10000, post, ArraySize(post), rawResult, headers);
       if(res!=200){
         Print("Errore nell'invio: ",GetLastError());
       }
       
       string response = CharArrayToString(rawResult);
       Print(response);
}