Reinstall Cups after unloading/removing its LaunchDaemon
Here are the commands I ran to solve this issue:
sudo launchctl stop org.cups.cupsd
sudo mv /etc/cups/cupsd.conf /etc/cups/cupsd.conf.backup
sudo cp /etc/cups/cupsd.conf.default /etc/cups/cupsd.conf
sudo mv /etc/cups/printers.conf /etc/cups/printers.conf.backup
sudo launchctl start org.cups.cupsd

Then I've reset the Printing System as suggested here:
https://support.apple.com/en-gb/HT203343
Then simply add your printers again.