Just received 2 emails from google, dated yesterday and today informing me that they have been unable to send me notifications.
We've made several unsuccessful attempts to send order notifications to your notification callback URL, https://secure.ebid.net/perl/googlecheckout_in.cgi As a result you aren't receiving order status, risk or other notifications.As I said this has only happened since yesterday, never had this problem before.We encountered an error processing your notification acknowledgment. The error we got is: Expected serial number was not contained in request. Merchant has enabled serial number notification handshake.