Apparmor profile for unbound log

mcedit  /etc/apparmor.d/usr.sbin.unbound

• Add this line (Here you should write a path to your "unbound.log" file. ):

# Site-specific additions and overrides for usr.sbin.unbound.
# For more details, please see /etc/apparmor.d/local/README.
/var/log/unbound/unbound.log rw,

Reload apparmor config and restart unbound services:

apparmor_parser -r /etc/apparmor.d/usr.sbin.unbound
service unbound restart

or

systemctl restart unbound