Cloud App Action Service - notification url is not called

Hi

I have created an Eloqua Cloud App with an Action Service.

To test it I created a campaign and added a couple of members but for some reason it seems like the notification url is not called at all.

It set the service up exactly like described here:Develop an AppCloud Action Service

My Notification URL is: http://URL/apps/components/notify?instance={InstanceId}&asset={AssetId}

I had a look in the log file (for the app) and there is no outbound call for the notification url either.

So the question is what am I doing wrong?

thanks,

Simon