Mea culpa, and you’re right here the permissions seem to be quite wrong:
root@nano-app:/var/www/discourse# sudo ls -l /etc/ssl/private/ssl-cert-snakeoil.key
sudo: /etc/sudo.conf is owned by uid 1000, should be 0
sudo: /etc/sudo.conf is owned by uid 1000, should be 0
sudo: error in /etc/sudo.conf, line 0 while loading plugin "sudoers_policy"
sudo: /usr/lib/sudo/sudoers.so must be owned by uid 0
sudo: fatal error, unable to load plugins
root@nano-app:/var/www/discourse#
What do you suggest to fix this?