null cookie upon redirecting from sandbox
<p>problem is that i am using paypal sandbox for testing purpose, whenever i redirect user to sandbox then i works fine, but upon return , it losses cookies and session too, i tried both , 
i am facing it for last 1 month but no progress, tried several forums but no help, 
First i used session, that works on everypage but not one the one to which sandbox is returning, i am using local host address and paypals successfully redirects back but losses session and cookie, </p>

<p>here i am creating cookie</p>

<pre><code>protected void Button1_Click(object sender, EventArgs e)
{
    String employerEmail = Request.QueryString["employerEmail"];
    HttpCookie employerEmailCookie = new HttpCookie("empEmailCookie", "defaulfCookieValue");
    employerEmailCookie["employerEmail"] = employerEmail;
    employerEmailCookie["CurrentDate"] = DateTime.Now.ToString();
    employerEmailCookie.Expires = DateTime.Now.AddMinutes(30);
    Response.Cookies.Add(employerEmailCookie);
    Response.Redirect("https://www.sandbox.paypal.com/us/cgi-bin/webscr?cmd=_xclick&amp;business=smile2_1355775057_biz@yahoo.com&amp;item_name=MemberShip&amp;amount=20&amp;currenc y=USD&amp;return=http://127.0.0.1:57135/Online%20Recruitment%20System-Final/paymentSuccessful.aspx?emailAdmin='"+employerEmail+"' &amp;cancel_return=https://www.google.com/" );
}
</code></pre>

<p>and this is the page to which i am redirecting back but it always give, COOKIE is null</p>

<pre><code>protected void Page_Load(object sender, EventArgs e)
{
    Page.DataBind();
    HttpCookie getEmployerEmailCookie = Request.Cookies["empEmailCookie"];
    if (getEmployerEmailCookie!= null)
    {
        String employerEmail = Request.QueryString["emailAdmin"];
        if (employerEmail == getEmployerEmailCookie.Value)
        {
            Response.Write("dear'" + getEmployerEmailCookie.Value + "',Your registration is successful");
        }
        else
        {
            Response.Write("No payment made");
        }
    }
    else 
    {
        Response.Write("Cookie is null");
    }
}
</code></pre>
