title: Why is the PayPal sandbox telling me my shopping cart is empty?
body: <p>On my local machine, when I submit this form, and I do have items inside the <code>$_SESSION['cart']</code>, the sandbox does recognize the items inside it. But when I tried it on a live server, and I submitted the form while there's an item inside <code>$_SESSION['cart']</code>, the sandbox says my cart is empty... Why is that?</p>
  
  <pre><code>&lt;form action="https://www.sandbox.paypal.com/cgi-bin/webscr" method="post" &lt;?php if(empty($_SESSION['cart'])){echo "onsubmit=\"return false;\"";} ?&gt;&gt;
      &lt;input type="hidden" name="cmd" value="_cart" /&gt;
      &lt;input type="hidden" name="upload" value="1" /&gt;
      &lt;input type="hidden" name="business" value="&lt;?=$ppemail['email']?&gt;" /&gt;
      &lt;?php
          $i = 1;
          foreach($_SESSION['cart'] as $id =&gt; $qty):
              $product = $myCart-&gt;getProduct($id);
      ?&gt;
              &lt;input type="hidden" name="item_name_&lt;?php echo $i; ?&gt;" value="&lt;?php echo $product['ProductName']; ?&gt;"&gt;
              &lt;input type="hidden" name="item_number_&lt;?php echo $i; ?&gt;" value="&lt;?php echo $product['ProductID']; ?&gt;"&gt;
              &lt;input type="hidden" name="amount_&lt;?php echo $i; ?&gt;" value="&lt;?php echo $product['ProductOverridePrice']; ?&gt;"&gt;
              &lt;input type="hidden" name="quantity_&lt;?php echo $i; ?&gt;" value="&lt;?php echo $qty; ?&gt;"&gt;
      &lt;?php
              $i++;
          endforeach;
      ?&gt;
      &lt;input type="hidden" name="currency_code" value="USD"&gt;
      &lt;input type="hidden" name="lc" value="US"&gt;
      &lt;input type="hidden" name="rm" value="2"&gt;
      &lt;input type="hidden" name="shipping_1" value="&lt;?php echo $shipping; ?&gt;"&gt;
      &lt;input type="hidden" name="return" value="&lt;?php echo $the_class-&gt;settings[0]['DomainName'];?&gt;shopping-cart-details.php"&gt;
      &lt;input type="hidden" name="cancel_return" value="&lt;?php echo $the_class-&gt;settings[0]['DomainName'];?&gt;"&gt;
      &lt;input type="hidden" name="notify_url" value="&lt;?php echo $the_class-&gt;settings[0]['DomainName'];?&gt;classes/paypal.php"&gt;
      &lt;input type="image" src="images/continue-btn.png" name="pay now" value="pay" /&gt;
  &lt;/form&gt;
  </code></pre>