I used on my href
<div class="col-xs-2 text-center">
<i class="fa fa-sign-out" style="font-size: 17px"><a href="../pages/loginpage.aspx?action=logout">Logout</a></i>
</div>
on my login page pageload following
if (Request.QueryString["action"] != null)
{
// response.clear();
Session.Abandon();
}
it works properly for me.