nTopNG installs but fails to run

,

NethServer Version: 7.8.2003
Module: nTopNG 2.2.2

I installed this module from cockpit but whenever I click on it in the Applications Tab I get:

Service Unavailable

The server is temporarily unable to service your request due to maintenance downtime or capacity problems. Please try again later.

You have to manually enable (or start) the service. You can do it from “System > Services”:

Many thanks

Andrew