Web Request, SyntaxError: Unexpected non-whitespace character after JSON.

[Giorgi Gachechiladze]

I have trouble with sending web Request. Seems it doesn't sends JSON raw correctly though body.

headers = "Content-Type: application/json\r"+"\n"+auth;
json[ACCOUNT_NUMBER] = accountNumber;
for(int i=0;i<1;i++)
{
        json[POSITION][i][P_OPEN_TIME] = TimeToString(position[i].ot);
        json[POSITION][i][P_POSITION] = IntegerToString(position[i].positionID);
        json[POSITION][i][P_SYMBOL] = position[i].symbol;
        json[POSITION][i][P_TYPE] = IntegerToString(position[i].type);
        json[POSITION][i][P_VOLUME] = DoubleToString(position[i].volume,3);
        json[POSITION][i][P_OPEN_PRICE] = DoubleToString(position[i].op,Digits());
        json[POSITION][i][P_CLOSE_TIME] = TimeToString(position[i].ct);
        json[POSITION][i][P_CLOSE_PRICE] = DoubleToString(position[i].cp,Digits());
        json[POSITION][i][P_COMMISSION] = DoubleToString(position[i].commission,2);
        json[POSITION][i][P_SWAP] = DoubleToString(position[i].swap,2);
        json[POSITION][i][P_PROFIT] = DoubleToString(position[i].profit,2);
}
StringToCharArray(json.Serialize(),data,0,WHOLE_ARRAY,CP_UTF8);
                
res = WebRequest("POST",url+"position",headers,timeout,data,result,result_headers);

[Giorgi Gachechiladze]

        string str = json.Serialize();
        StringToCharArray(str,data,0,WHOLE_ARRAY,CP_UTF8);
        ArrayResize(data,ArraySize(data)-1);

solution