cannot redirect

Dear all,
 
I have below code in Global.asax. But it seems making cannot redirect from login page in production environment where it has e-cert.
In Testing environment, it works with commenting below code in Global.asax.
//-------------------------------------------------------------------------------------------------------
protected void  Application_EndRequest(object sender, EventArgs e)
{
    if (Response.Cookies.Count > 0)
    {
        foreach (string s in Response.Cookies.AllKeys)
        {
            if (s == FormsAuthentication.FormsCookieName || s.ToLower() == "asp.net_sessionid")
            {
            ...