 
  
  app.UseStatusCodePages(async context =>
{
    var response = context.HttpContext.Response;
    if (response.StatusCode == (int)HttpStatusCode.Unauthorized)
       {
        response.Redirect("/account/signin");
       }
});services.AddAuthentication(CookieAuthenticationDefaults.AuthenticationScheme)
    .AddCookie(options => //CookieAuthenticationOptions
    {
        options.LoginPath = new Microsoft.AspNetCore.Http.PathString("/Logon");
    });