Package: cups Version: 1.7.5-11+deb8u1 Printing had been working fine for a long time but about 20 minutes ago I tried to print something and an error popup appeared in GNOME asking if I wanted to diagnose the printer. My document appeared paused in the queue.
I looked at /var/log/cups/*log and found nothing about the error I went to the control panel and also the CUPS web interface on port 631 and tried re-enabling the printer and each time I did that it failed again. I looked at /var/log/daemon.log and observed: hpcups[16590]: prnt/hpcups/HPCupsFilter.cpp 707: First raster data plane.. hp[16592]: io/hpmud/jd.c 820: mdns lookup ABC123DEF.local retry 1... hp[16592]: io/hpmud/jd.c 820: mdns lookup ABC123DEF.local retry 2... hp[16592]: io/hpmud/jd.c 820: mdns lookup ABC123DEF.local retry 3... hp[16592]: io/hpmud/jd.c 820: mdns lookup ABC123DEF.local retry 4... hp[16592]: io/hpmud/jd.c 820: mdns lookup ABC123DEF.local retry 5... hp[16592]: io/hpmud/jd.c 820: mdns lookup ABC123DEF.local retry 6... hp[16592]: io/hpmud/jd.c 820: mdns lookup ABC123DEF.local retry 7... hp[16592]: io/hpmud/jd.c 820: mdns lookup ABC123DEF.local retry 8... hp[16592]: io/hpmud/jd.c 820: mdns lookup ABC123DEF.local retry 9... hp[16592]: io/hpmud/jd.c 820: mdns lookup ABC123DEF.local retry 10... hp[16592]: io/hpmud/jd.c 820: mdns lookup ABC123DEF.local retry 11... hp[16592]: io/hpmud/jd.c 820: mdns lookup ABC123DEF.local retry 12... hp[16592]: io/hpmud/jd.c 820: mdns lookup ABC123DEF.local retry 13... hp[16592]: io/hpmud/jd.c 820: mdns lookup ABC123DEF.local retry 14... hp[16592]: io/hpmud/jd.c 820: mdns lookup ABC123DEF.local retry 15... hp[16592]: io/hpmud/jd.c 820: mdns lookup ABC123DEF.local retry 16... hp[16592]: io/hpmud/jd.c 820: mdns lookup ABC123DEF.local retry 17... hp[16592]: io/hpmud/jd.c 820: mdns lookup ABC123DEF.local retry 18... hp[16592]: io/hpmud/jd.c 820: mdns lookup ABC123DEF.local retry 19... hp[16592]: io/hpmud/jd.c 820: mdns lookup ABC123DEF.local retry 20... hp[16592]: io/hpmud/jd.c 816: error timeout mdns lookup ABC123DEF.local hp[16592]: io/hpmud/jd.c 93: unable to read device-id hp[16592]: prnt/backend/hp.c 808: ERROR: open device failed stat=12: hp:/net/HP_LaserJet_3055?zc=ABC123DEF I killed the cups process and modified /etc/cups/printers.conf to change the URI from: DeviceURI hp:/net/HP_LaserJet_3055?zc=ABC123DEF to something like: DeviceURI hp:/net/HP_LaserJet_3055?ip=192.168.1.234 and started cups again and now printing works again. What is really wrong here? Why did the popup not tell me the root cause of the problem? Why did I have to go hunting around in the log files like this? How many non-developers would be comfortable troubleshooting a problem like that without more details?