transmission-daemon: error loading working config-file. User priveliges?

Problem solved!

The folder

/var/lib/transmission-daemon/

als needs to be owned by the correct user, so in addition to the commands stated in my question above:

sudo chown -R robots:robots /var/lib/transmission-daemon/ 

Replace the user "robots" and the group "robots" to the names used on your system.

Debian users may take a look at file: /lib/systemd/system/transmission-daemon.service to verify the required user is also set in that file.

Then, verify the home directory for that user because the configuration will then be read from ~/.config/transmission-daemon/

Empty file /etc/transmission-daemon/settings.json invokes this error in my case.

rm /etc/transmission-daemon/settings.json solves problem.

Debug hinit: sudo -u debian-transmission strace transmission-daemon -f --log-debug -g /etc/transmission-daemon/