[asp.net] FormsAuthentication.SignOut() does not log the user out

After lots of search finally this worked for me . I hope it helps.

public ActionResult LogOff()
{
    AuthenticationManager.SignOut();
    HttpContext.User = new GenericPrincipal(new GenericIdentity(string.Empty), null);
    return RedirectToAction("Index", "Home");
}

<li class="page-scroll">@Html.ActionLink("Log off", "LogOff", "Account")</li>