Google Checkout callback issue - php

Question

I am trying to (using a sandbox account) sell items using google checkout. I am displaying a form to the user which results in a buy now button
<form method="POST" action="https://sandbox.google.com/checkout/api/checkout/v2/checkoutForm/Merchant/..." accept-charset="utf-8">
<input type="hidden" name="item_name_1" value="Test"/>
<input type="hidden" name="item_description_1" value="An item "/>
<input type="hidden" name="item_quantity_1" value="1"/>
<input type="hidden" name="item_price_1" value="1.50"/>
<input type="hidden" name="item_currency_1" value="GBP"/>
<input type="hidden" name="_charset_"/>
<input type="hidden" name="checkout-flow-support.merchant-checkout-flow-support.continue-shopping-url" value="redirect to this url"/>
<input type="image" name="Google Checkout" alt="Fast checkout through Google" src="http://sandbox.google.com/checkout/buttons/checkout.gif?merchant_id=....&w=180&h=46&style=white&variant=text&loc=en_US" height="46" width="180"/>
</form>
On the google seller account i am setting the url to be called back too. In this instance i am using the php file from the google docs example
// Include Google Checkout PHP Client Library
include ("GlobalAPIFunctions.php");
// Include Response Message Processor
include ("ResponseHandlerAPIFunctions.php");
// Retrieve the XML sent in the HTTP POST request to the ResponseHandler
$xml_response = $HTTP_RAW_POST_DATA;
// Get rid of PHP's magical escaping of quotes
if (get_magic_quotes_gpc()) {
$xml_response = stripslashes($xml_response);
}
// Log the XML received in the HTTP POST request
LogMessage($GLOBALS["logfile"], $xml_response);
/*
* Call the ProcessXmlData function, which is defined in
* ResponseHandlerAPIFunctions.php. The ProcessXmlData will route
* the XML data to the function that handles the particular type
* of XML message contained in the POST request.
*/
ProcessXmlData($xml_response);
The issue is, as soon as i buy an item i get no call back whatsoever. No error message, no nothing so how can i see what is going on? Hopefully someone could help me out
Thanks

Answer 1

Check your Sandbox Integration Console for errors (if any) - just making sure that you are referring to your sandbox account (sandbox and production accounts are distinct)
On the google seller account i am setting the url to be called back too
"too" - just making sure. There is only one place where you set the API Callback URL - and that is in your Account Integration Settings (so there is no "too").
<input type="hidden" name="checkout-flow-support.merchant-checkout-flow-support.continue-shopping-url" value="redirect to this url"/>
Again, just clarifying that you are not referring to the above as the callback api url. The above is the link presented to a buyer after purchase (it's just a link back to your web site). It is not the callback api url.