ASP.NET Formauthentication.Signout() not working - asp.net

Question

I am using forms authentication for a web site I am building and it works out pretty well except I cannot get the auth cookie to delete or expire. I have tried any number of methods and none of them seem to work. Here is what I create the cookie.
FormsAuthentication.SetAuthCookie(model.userName, false);
HttpCookie cookie = new HttpCookie("user");
Response.Cookies["user"].Value = model.userName;
Now the second cookie isn't an actual authcookie, that is used for some of the inner workings of the site per client request. This next part are various things I have tried to delete the cookie.
FormsAuthentication.SignOut();
Roles.DeleteCookie();
Session.Clear();
//Response.Cache.SetExpires(DateTime.Now);
//foreach (var cookie in Request.Cookies.AllKeys)
//{
// Request.Cookies.Remove(cookie);
//}
//foreach (var cookie in Response.Cookies.AllKeys)
//{
// Response.Cookies.Remove(cookie);
//}
//Session.Abandon();
//// clear authentication cookie
HttpCookie cookie1 = new HttpCookie(FormsAuthentication.FormsCookieName, "");
cookie1.Path = FormsAuthentication.FormsCookiePath;
cookie1.Expires = DateTime.Now.AddYears(-1);
Response.Cookies.Add(cookie1);
HttpCookie cookie = Request.Cookies["user"];
string userName = cookie.Value;
cookie.Expires.AddDays(-30);
//HttpCookie cookie2 = new HttpCookie("ASP.NET_SessionId", "");
//cookie2.Expires = DateTime.Now.AddYears(-1);
//Response.Cookies.Add(cookie2);
//HttpCookie cookie = Request.Cookies["user"];
//cookie.Expires = DateTime.Now.AddDays(-1d);
//HttpCookie user = Request.Cookies["user"];
//role.Expires = DateTime.Now.AddDays(-1d);
//Response.Cookies["user"].Value = null;
Session.Abandon();
I just cut and paste the entire thing in there, some of it is commented out now but at some point and time I have attempted to use each method in that code to remove the cookie. Some of these attempts were just guesses since I have been at this for a while. Last here is the auth section of my web.config
<authentication mode="Forms" >
<forms loginUrl="~/login" timeout="90" name=".ASPXFORMS" />
</authentication>
Any input as to what I am doing wrong is appreciated.

Answer 1

Try calling
FormsAuthentication.SignOut()
Before calling session. I generally place this in a separate method to make it easy to call from multiple places. Something like this:
internal void SignOut(HttpContext context)
{
FormsAuthentication.SignOut();
HttpSessionState session = context.Session;
if(session != null)
{
session.Abandon();
}
}