I’ve installed the fess on ubunto 18.4 and it is running. but http://localhost:8080 shows me apache front page and http://localhost:8080/admin and http://localhost:8080/fess produce the following message:
Not Found
The requested URL was not found on this server.

I am using apache2.4.29 as web server.
Am I miss something here?

Did you check fess.log?

This issue is resolved.