If you are expecting, but not receiving Platform Notifications, below are some Tips to help you triage this problem.
Use this call to query eBay's notifications logs for information on your notification event and delivery status.
Notifications are only delivered to port 80 and it is not necessary to specify the port number in your URL. Make sure your Platform Listener URL is not behind a firewall, and is completely accessible. If your URL is not accessible, it will be noted as a timeout from the GetNotificationsUsage call:
[Notification HttpEventSender Error: com.ebay.kernel.service.invocation.client.exception.ReceivingTimeoutException: Socket read from www.samplelistener.com timed out after 3,000 milli-seconds.]
Use the GetNotificationPreferences Call to check your application level subscription status and URL
Use the GetNotificationPreferences Call to verify that your user is subscribed to all expected Notification Events
When you Platform Notifications Listener receives an incoming notification, it should response to the eBay server with a 200 OK response. A successful 200 OK response will be displayed in the GetNotificationsUsage response like this:
<ErrorMessage>|[Notification HttpEventSender: URL http://sandbox.samplelistner.net/ebaynotification.asmx: HTTP Client returned 'Success' (HTTP status: 200, 'OK')]</ErrorMessage>
or <ErrorMessage>|SMTPEventSender: Sent successfully</ErrorMessage> if your DeliveryURL is set to an email address.
Alternatively, you can verify that your web server is responding with a 200 OK response by looking at your web server logs.