For me too. Ntop never worked. just tries to connect on port 3000 but no data sent to the web browser. My version is Nethserver 7.3 RC3 (all updates installed). Would be cool to see an update on this.
I have NTOP installed on my server and never had any problems with it. Can you access the NTOP webinterface? (do you get a login screen?)
Is the service running? See ‘services’ in NS webinterface: ntopng (Network traffic analyzer) Enabled Running TCP: 3000
Took a look. Looks like it’s disabled by default but interface doesn’t make that clear on the install. Perhaps something to let people know so they don’t have to hunt in different screens on installation would be useful.