Lubuntu 20.04 automatically discovered my printer on my LAN. However, printing does not work. Tried printing a PDF from Firefox, and got a popup error message:
‘Dell_Color_MFP_E525w_02_99_1B_’: ‘cups-pki-expired’
Printing works fine from my other systems.
Looking in the logs, I saw that AppArmor was denying cupsd access to several things. I disabled AppArmor, but printing still does not work. If I go into the printer dialog, in Printer Properties, under the Policies tab, I see that the printer is not enabled. If I enable it, it seems to work, but within a few seconds, it goes back to not enabled.
/var/log/syslog:
Apr 28 08:07:37 moo dbus-daemon[720]: [system] Activating service name=‘org.opensuse.CupsPkHelper.Mechanism’ requested by ‘:1.57’ (uid=1000 pid=1332 comm=“/usr/bin/python3 /usr/share/system-config-printer/” label=“unconfined”) (using servicehelper)
Apr 28 08:07:37 moo dbus-daemon[720]: [system] Successfully activated service ‘org.opensuse.CupsPkHelper.Mechanism’
Apr 28 08:07:38 moo systemd-resolved[707]: Server returned error NXDOMAIN, mitigating potential DNS violation DVE-2018-0001, retrying transaction with reduced feature level UDP.
/var/log/cups/access_log:
localhost - - [28/Apr/2020:08:07:37 -0500] “POST /admin/ HTTP/1.1” 401 185 Resume-Printer successful-ok
localhost - cups-pk-helper [28/Apr/2020:08:07:37 -0500] “POST /admin/ HTTP/1.1” 200 185 Resume-Printer successful-ok
localhost - cups-pk-helper [28/Apr/2020:08:07:37 -0500] “POST /admin/ HTTP/1.1” 200 208 CUPS-Add-Modify-Printer successful-ok
localhost - root [28/Apr/2020:08:07:38 -0500] “POST /admin/ HTTP/1.1” 200 297 CUPS-Add-Modify-Printer successful-ok
/var/log/cups/error_log:
W [28/Apr/2020:07:38:17 -0500] CreateProfile failed: org.freedesktop.DBus.Error.NoReply:Did not receive a reply. Possible causes include: the remote application did not send a reply, the message bus security policy blocked the reply, the reply timeout expired, or the network connection was broken.
W [28/Apr/2020:07:38:19 -0500] CreateProfile failed: org.freedesktop.ColorManager.AlreadyExists:profile id 'Dell_Color_MFP_E525w_02_99_1B_-Gray…' already exists
W [28/Apr/2020:07:38:19 -0500] CreateProfile failed: org.freedesktop.ColorManager.AlreadyExists:profile id 'Dell_Color_MFP_E525w_02_99_1B_-DeviceN…' already exists
After setting CUPS to debug2 level output, error_log contains:
D [28/Apr/2020:08:28:41 -0500] [Job 1] update_reasons(attr=0(), s="-cups-certificate-error")
d [28/Apr/2020:08:28:41 -0500] [Job 1] op='-', new_reasons=1, state_reasons=1
D [28/Apr/2020:08:28:41 -0500] [Job 1] Connection is encrypted.
d [28/Apr/2020:08:28:41 -0500] select_timeout: JobHistoryUpdate=0
D [28/Apr/2020:08:28:41 -0500] [Job 1] Credentials are expired (Credentials have expired.)
D [28/Apr/2020:08:28:41 -0500] [Job 1] Printer credentials: DELL02991B (issued by unknown) / Wed, 02
Jan 2019 00:00:00 GMT / RSA-SHA256 / A1D969DB328B48E674BE84EDC8C2D18D
d [28/Apr/2020:08:28:41 -0500] select_timeout: JobHistoryUpdate=0
D [28/Apr/2020:08:28:41 -0500] [Job 1] No stored credentials.
D [28/Apr/2020:08:28:41 -0500] [Job 1] update_reasons(attr=0(), s="-cups-pki-invalid,cups-pki-change
d,cups-pki-expired,cups-pki-unknown")
d [28/Apr/2020:08:28:41 -0500] [Job 1] op='-', new_reasons=4, state_reasons=1
D [28/Apr/2020:08:28:41 -0500] [Job 1] update_reasons(attr=0(), s="+cups-pki-expired")
d [28/Apr/2020:08:28:41 -0500] [Job 1] op='+', new_reasons=1, state_reasons=1
D [28/Apr/2020:08:28:41 -0500] [Job 1] STATE: +cups-pki-expired
d [28/Apr/2020:08:28:41 -0500] cupsdSetPrinterReasons(p=0x55b3a136ac00(Dell_Color_MFP_E525w_02_99_1B_),s=“+cups-pki-expired”
One recommendation was to change client.conf setting AllowExpiredCerts from the default, which is No, to Yes. But there is no client.conf file. I’ve run out of ideas for now.