Avahi rejects cups print jobs after system upgrade

Question

I recently upgraded my system from RHEL 6.5 to 7.2. A previously working network printer stopped working. The printer is configured as before with the same driver and options. Trying to print a simple PDF document, all I can see in terms of error is in /var/log/messages (/var/logs/cups/error_log does not have an error):

Apr 28 09:53:49 machineName dbus[942]: [system] Rejected send message, 10 matched rules; type="method_return", sender=":1.151" (uid=70 pid=12531 comm="avahi-daemon: starting up ") interface="(unset)" member="(unset)" error name="(unset)" requested_reply="0" destination=":1.87" (uid=500 pid=23243 comm="evince /home/user/xxxx")

Apr 28 09:53:49 machineName dbus[942]: [system] Rejected send message, 10 matched rules; type="method_return", sender=":1.151" (uid=70 pid=12531 comm="avahi-daemon: starting up ") interface="(unset)" member="(unset)" error name="(unset)" requested_reply="0" destination=":1.87" (uid=500 pid=23243 comm="evince /home/user/xxxxx")

Apr 28 09:53:49 machineName dbus-daemon: dbus[942]: [system] Rejected send message, 10 matched rules; type="method_return", sender=":1.151" (uid=70 pid=12531 comm="avahi-daemon: starting up ") interface="(unset)" member="(unset)" error name="(unset)" requested_reply="0" destination=":1.87" (uid=500 pid=23243 comm="evince /home/user/xxxxx")

The printer is connected via USB to a print server in the local network. Other machines can reach the printer and successfully print. Is this a network issue with avahi? Do I need to create a service file? Anything else to look into?

Answer 1

(After some more hours of debugging) The error is caused by SELinux policies.

sudo getenforce shows enforced, i.e., SELinux is on. After turning it off via sudo setenforce 0 it is possible to print. I found some documentation by Brother that has some guidance on how to keep SELinux enabled and still being able to print. It involves adding some policies and re-applying them to the installed driver files.