title: paypal IPN not sending any notification
body: <p>I have integrated paypal with my website and but it does take the payment but it doesnot send any IPN to my php file which should update my databse....
  there is the code I have been using:
   to call</p>
  
  <pre><code>session_start();
  if($mode=='live')
  {
      $url=" https://www.paypal.com/cgi-bin/webscr";
      $email="nnnnnnn_singh@live.com";
      $_SESSION['url']=$url;
      $_SESSION['email']=$email;
      $_SESSION['subtotal']=$subtotal;
  }
  else if($mode=='sandbox')
  {
      $url= "https://www.sandbox.paypal.com/cgi-bin/webscr";
      $email="nnnnnnn_1329707350_biz@gmail.com";
      $_SESSION['url']=$url;
      $_SESSION['email']=$email;
      $_SESSION['subtotal']=$subtotal;
  }
  ?&gt;
  
                  &lt;form action="&lt;?php echo $url; ?&gt;" method="post"&gt;
                  &lt;input type="hidden" name="cmd" value="_xclick"/&gt;
                  &lt;input type="hidden" name="business" value="&lt;?php echo $email; ?&gt;"/&gt;
                  &lt;input type="hidden" name="item_name" value="shopping cart"/&gt;
                  &lt;input type="hidden" name="currency_code" value="GBP"/&gt;
                  &lt;input type="hidden" name="amount" value="&lt;?php echo $subtotal;?&gt;"/&gt;
                  &lt;input type="hidden" name="return" value="&lt;?php echo SITE_URL; ?&gt;"/&gt;
                  &lt;input type="hidden" name="cancel_return" value="&lt;?php echo SITE_URL."/shoppingCart.php" ?&gt;"/&gt;
                  &lt;input type="hidden" name="notify_url" value="php url" /&gt;
                  &lt;input type="hidden" name="rm" value="2"/&gt;
                  &lt;input type="hidden" name="custom" value="&lt;?php echo $customer_ID;?&gt;"/&gt;
                  &lt;input type="image" src="http://www.paypal.com/en_US/i/btn/x-click-but01.gif" name="submit" alt="Make payments with PayPal - it's fast, free and secure!"/&gt;
                  &lt;/form&gt;
  </code></pre>
  
  <p>and php code</p>
  
  <p>from php IPN  sample code.....</p>