Follow the instructions from the below link to Enable REST Web services and port, allow non-SSL connections and set port, configure proxy for Client.
The Client REST interface is not available over the network. For security reasons, only requests from
localhost are allowed. The functionality that uses the interface must reside on the same machine as the AppMon Client.
Review the links for better understanding about the Client and Sever Interfaces.
I couldnot able to access the mentioned link, seems permission issue, need help to get access the url. Since i have also same kind of requirement to enable the REST service monitoring to monitor their response times.