Cannot Append to cookie in ASP.NET Core 2.0 MVC

Hello,

I am trying perform a very simple action

using System;
using System.Collections.Generic;
using System.Linq;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
var mtaUserCookie = Request.Cookies["mtaUserRole"];
if (mtaUserCookie != null)
{
Response.Cookies.Delete("mtaUserRole");
}
try
{
var cookieName = "mtaUserRole";
Response.Cookies.Append(cookieName, "IsAppAdmin");
}
catch ( Exception e ){ e.Message.ToString(); } // no errors...

// debug code
var mtaUserCookie = Request.Cookies["mtaUserRole"]; // value is null here

Please help.