DataSnap Error with Indy

I made a server application calling the browse , everything works fine, but to test my methods I built a client using TdHTTP o and call the methods as follows:

procedure TF_CLIENTE.SBEnviar2Click(Sender: TObject);
var Url        : String;
    lJSO       : String;
    jsonToSend : TStringStream;
begin

  Url := 'http://localhost:809...ecomandoPOST/';

  lJSO                                    := ('{"name":"TESTE"}');
  jsonToSend                              := TStringStream.Create(lJSO,TEncoding.UTF8);

  idHttp.ProxyParams.Clear;
  idHttp.ProxyParams.BasicAuthentication  := false;
  idHttp.Request.BasicAuthentication      := True;
  idHttp.Request.Accept                   := 'text/javascript';
  IdHTTP.Request.ContentType              := 'application/json';
  IdHTTP.Request.ContentEncoding          := 'utf-8';
  idHttp.Request.Method                   := 'POST';
  IdHTTP.Request.BasicAuthentication      := True;
  IdHTTP.Request.Authentication           := TIdBasicAuthentication.Create;
  IdHttp.Request.Authentication.Username  := 'USUARIO';
  IdHttp.Request.Authentication.password  := 'SENHA';
  IdHttp.Request.ContentLength            := Length(lJSO);
  try
    Memo1.Text := idHttp.Post(Url,jsonToSend);
  except
    on E : Exception do
      begin
        Memo1.Lines.Add('Exception class name = '+E.ClassName);
        Memo1.Lines.Add('Exception message = '+E.Message);
      end;
  end;

end;

I've already released Dispatch :

procedure TF_WebModule.WebModuleBeforeDispatch(Sender: TObject;
  Request: TWebRequest; Response: TWebResponse; var Handled: Boolean);
begin
  Response.SetCustomHeader('access-control-allow-origin','*');
  Response.SetCustomHeader('access-control-allow-Methods','PUT, POST, GET, DELETE');
  Response.SetCustomHeader('access-control-allow-Headers','accept, authorization, origin');
  if FServerFunctionInvokerAction <> nil then
  FServerFunctionInvokerAction.Enabled := AllowServerFunctionInvoker;
end;

I've already validated the user and comes up with the Indy Authentication:

procedure TF_WebModule.DSAuthenticationManager1UserAuthenticate(Sender: TObject;
  const Protocol, Context, User, Password: string; var valid: Boolean;
  UserRoles: TStrings);
begin

  if Request.Method = 'OPTIONS' then
    valid := False
  else
    if ((User = 'USUARIO') and (Password = 'SENHA')) then
      valid := True
    else
      valid := False;

end;

It has an error:

  

Exception class name = EIdHTTPProtocolException Exception message =   HTTP / 1.1 500 Internal Server Error