Hi Rajesh,
Good to know that now it runs error free. For notifications not reaching the HTTP Listener, it may happen that your notification is still locked in the queue. Go to transaction SBGRFCMON and check, if there is any locked queue. Try to process the queue manually. It should work fine.
is there any other way know wether the notification been sent to destination
Yes, you can use a HTTP handler class in your ABAP server. You can expose a class as SICF service. Then create a RFC destination (HTTP destination) to your server where that class is hosted. Then subscribe the entityset with the URL(with fully qualified domain name) of just created class. Set a external breakpoint in the class. Once the gateway processes the notification, your debugger will start.
To create a HTTP handler class, check the replyRe: Creating a Web Service from a Class. Your class must be inheriting from the interface "IF_HTTP_EXTENSION" and you need to implement "HANDLE_REQUEST" method.