I get the same error: not sure why it says active (exited).
root@pi-hole2:~# service pihole-FTL restart
root@pi-hole2:~# systemctl status pihole-FTL
● pihole-FTL.service - LSB: pihole-FTL daemon
Loaded: loaded (/etc/init.d/pihole-FTL; bad; vendor preset: enabled)
Active: active (exited) since Sat 2018-08-11 16:12:53 UTC; 2s ago
Docs: man:systemd-sysv-generator(8)
Process: 2983 ExecStop=/etc/init.d/pihole-FTL stop (code=exited, status=0/SUCCESS)
Process: 2987 ExecStart=/etc/init.d/pihole-FTL start (code=exited, status=0/SUCCESS)
Aug 11 16:12:53 pi-hole2 systemd[1]: Starting LSB: pihole-FTL daemon...
Aug 11 16:12:53 pi-hole2 pihole-FTL[2987]: Not running
Aug 11 16:12:53 pi-hole2 pihole-FTL[2987]: chown: cannot access '/etc/pihole/dhcp.leases': No such file or directory
Aug 11 16:12:53 pi-hole2 pihole-FTL[2987]: Failed to set capabilities on file `/usr/bin/pihole-FTL' (Invalid argumen
Aug 11 16:12:53 pi-hole2 pihole-FTL[2987]: The value of the capability argument is not permitted for a file. Or the
Aug 11 16:12:53 pi-hole2 su[3011]: Successful su for pihole by root
Aug 11 16:12:53 pi-hole2 su[3011]: + ??? root:pihole
Aug 11 16:12:53 pi-hole2 su[3011]: pam_unix(su:session): session opened for user pihole by (uid=0)
Aug 11 16:12:53 pi-hole2 pihole-FTL[2987]: dnsmasq: failed to create listening socket for port 53: Permission denied
Aug 11 16:12:53 pi-hole2 systemd[1]: Started LSB: pihole-FTL daemon.