SOLVED: Jellyfin service not starting

[dmf]

I had the same problem and nothing in the thread so far helped but I managed to fix it. 
I ran

Code:

sudo journalctl -u jellyfin

which basically told me that access to the path '/etc/jellyfin/logging.default.json' is denied.
I used

Code:

sudo chown -R jellyfin:jellyfin /etc/jellfin

and

Code:

sudo chmod -R 755 /etc/jellyfin

to modify permissions and it basically fixed it.

If nothing in this thread seems to work just run the first command, it may give you more clues as to what is wrong. Hope it helps.