Apparmor Init Failed, Exit Code 123
Seems to be a reported bug (#1554803)
It can be solved installing apparmor-easyprof-ubuntu or creating the folders by hand.
sudo apt-get install apparmor-easyprof-ubuntu
In my case the problem appeared when I uninstalled the snapd package with apt-get remove snapd. Checking the syslog, it seems the snapd uninstaller deleted some directories but not the apparmor config files referencing them. I pruned the package with apt-get purge snapd and restarted apparmor without errors.