So if the change to the AppArmor profile hasn't helped (other than to silence this message) then I suspect that is not the real issue. Perhaps this is related to the snap's device cgroup?
There is good documentation on debugging snaps at https://forum.snapcraft.io/t/debugging-snaps/18420 - in particular perhaps the section on file permissions might shed some light in this case - https://forum.snapcraft.io/t/debugging-snaps/18420#heading-- permissions -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1950855 Title: Can't enable snap to print on a usb printer To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/snapd/+bug/1950855/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs