Probably permissions problems.
root@server:~# tvheadend -p /run/tvheadend.pid -u hts -g hts -c /home/hts
2019-04-19 09:26:26.640 [ NOTICE] START: HTS Tvheadend version 4.3-1789~g6bfeca6c0 started, running as PID:30048 UID:1 GID:1, CWD:/root CNF:/home/hts
tvheadend is running as root:root (UID:1 GID:1), should be runnning as hts:video
not sure why it is at least not showing hts:hts as requested on the command line???
tvheadend -p /run/tvheadend.pid -u hts -g video -c /home/hts
Check permissions of dvb:
ls -alR /dev/dvb
Or run as hts user but add hts user to the video group...