Google Checkout Error

[charrabennett]

I am getting emails from Google Checkout daily on the below error but I have done all of the steps to fix it and when I follow the steps in the error - everything is right? I have also tested the shop and successfully placed 2 orders with google checkout with no error message. Please help me find out what is causing google to send me this error.

We've made several unsuccessful attempts to send order notifications to your notification callback URL, https://www.futtermansstationery.com/modules/gcheckout/validation.php As a result, you aren't receiving order status, risk, or other notifications.


To help you identify the issue with your callback URL, please review the errors we encountered while sending notifications to you. To review this error information:
Sign in to Google Checkout.
Click on the Tools tab.
Click Integration Console.
Error messages will appear under 'Integration Issues.' If necessary, you can also update your callback URL in the 'API callback URL' box on the same page.
For more information about receiving notifications via the notification API, visit http://code.google.com/apis/checkout/developer/index.html#notification.