I have a made a ASP.NET membership provider, it works well but I notice that if the user changes passwords signs out and then tries to sign in again it fails, this also happends if the user has two or more accounts and signs out with one and tries to sign in with the other. If the user clears cookies in the browser he/she can sign in again, so it seems that when the user signs out the cookies are not deleted for some reason. Here is my sign out code:

```
void ClearAuthenticationCookie()
    {
        var cookie1 = new HttpCookie(FormsAuthentication.FormsCookieName, String.Empty) { Expires = DateTime.Now.AddYears(-1) };
        Response.Cookies.Add(cookie1);            
    }

    protected void Page_Load(object sender, EventArgs e)
    {
        FormsAuthentication.SignOut();

        ClearAuthenticationCookie();

        FormsAuthentication.RedirectToLoginPage();
    }

```