I changed /etc/apparmor.d/usr.sbin.cupsd and added /etc/* r, in the list of directories, this fixed it, I think it's because it has to read the /etc/pnm2ppa.conf file.
I changed /etc/apparmor. d/usr.sbin. cupsd and added
/etc/* r,
in the list of directories, this fixed it, I think it's because it has to read the /etc/pnm2ppa.conf file.