You must create a type G RFC destination with the delivery address given in the subscription request body to allow the notification to be delivered to the user.
The delivery address is that of the SAP connectivity service.
The SAP connectivity service on-demand component resides in the customer's on premise environment. It is responsible for enabling the connectivity from the SAP connectivity service servers, located in SAP's on-demand environment, to the customer's SAP Gateway instance, located in customer's on-premise environment.
To create a type G RFC destination:
In the SAP Gateway system, open transaction SPRO.
Choose SAP Reference IMG.
Choose Execute. The Configuration of RFC Connections page is displayed.
In the RFC Destination field, enter the desired name, for example GW_RFC.
In the Connection Type field, press F4 and select G HTTP Connection to External Server.
Under the Technical Settings tab, in the Description field, enter the desired description.
An Information dialog box is displayed. Choose the checkmark to continue.
In the Target Host field, enter the host IP.
In the Service No. field, enter the port number.
In the Path Prefix field, enter any additional directories, if relevant.
If relevant, select the Logon & Security tab.
Enter the security settings as required.
To continue with the flow, go to Configuring User Authorizations for Push Notifications.