What is the status of this issue with nop v2.3 as I am now getting emails from Google Checkout stating the following and I have tried Google Checkout API v2.4 and v2.5 with nop
NopVersion 2.4 with ssl enabled, We have just had the same error report back form Google.
We've made several unsuccessful attempts to send order notifications to your notification callback URL, https://robertemslie.co.uk/Plugins/PaymentGoogleCheckout/NotificationHandler As a result, you aren't receiving order status, risk or other notifications.
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.
The detail are 924392469677437 Time of occurrence: 20 Mar 2012 06:16:33 PDT Error: We encountered an error trying to access your server at https://robertemslie.co.uk/Plugins/PaymentGoogleCheckout/NotificationHandler -- the error we got is java.io.IOException: Error 'SSL_CERTIFICATE_ERROR' connecting to url 'https://robertemslie.co.uk/Plugins/PaymentGoogleCheckout/NotificationHandler'. More documentation for this error.
I suspect we have an explanation. My server support Appliedi.net have just confirmed that the cause of my difficulty will very likely be my SSL certificate is not accepted by Google.
I notice you are using the Positive SSL certificate. Unfortunately there are issues with the Positive SSL and Google Checkout, so this method will not work. https://support.google.com/checkout/sell/bin/answer.py?hl=en&answer=134466&from=57856&rd=1