How to use [Authorize] attribute in project which using MVC Portable Areas

My project using MVC Portable Areas, its contain 2 projects, one is the main, and the other is Account project. In AccountController, I use [Authorize] attribute to redirect user to Login page, but I always receive "You don't have permission to access this directory". Any solution for me?

Controller code:

[Authorize]
public partial class AccountController : Controller
{
    [AllowAnonymous]
    public virtual ActionResult Login(string returnUrl)
    {
        ViewBag.ReturnUrl = returnUrl;
        return View();
    }
}

Root Web.config:

<authentication mode="Forms">
  <forms name=".FORM" loginUrl="area/account/login" protection="All" timeout="30" path="/"/>
</authentication>

It works without any problems in my project which using MVC Portable Areas.

Also, make sure that [Authorize] attribute redirect to the correct page and correct action method