I have problems again with accessing my HP M281fdw LaserJet printer. It started with the fact that scanning did not work any more.

See bug 1694663 for details on problems that I had before.

In an attempt to get my LaserJet scanning again, I installed hp-plugin. The scanner did still not work. Next, I removed
/usr/share/hplip/data/models/models.dat
because I did this in the past once as well, and reinstalled hplip:
# dnf reinstall hplip*

Next I removed the two entries of the LaserJet in Gnome-Settings|Printers (the avahi discovered one and the previously manually added one).

Then I tried to reinstall the LaserJet from Gnome-Settings|Printers. But this results now in a Failed to add new printer popup window.

Here is an excerpt from my journal:

Nov 17 20:01:52 nyx gnome-shell[2579]: invalid (NULL) pointer instance
Nov 17 20:01:52 nyx gnome-shell[2579]: g_signal_handler_disconnect: assertion 'G_TYPE_CHECK_INSTANCE (instance)' failed
Nov 17 20:01:54 nyx gnome-keyring-daemon[2497]: asked to register item /org/freedesktop/secrets/collection/login/53, but it's already registered
Nov 17 20:01:54 nyx gnome-keyring-daemon[2497]: asked to register item /org/freedesktop/secrets/collection/login/52, but it's already registered
Nov 17 20:01:58 nyx systemd[1]: Started dbus-:1.5-org.opensuse.CupsPkHelper.Mechanism@2.service.
Nov 17 20:01:58 nyx audit[1]: SERVICE_START pid=1 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:init_t:s0 msg='unit=dbus-:1.5-org.opensuse.CupsPkHelper.Mechanism@2 comm="systemd" exe="/usr/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
Nov 17 20:01:58 nyx cupsd[1713]: REQUEST localhost - - "POST / HTTP/1.1" 401 98 CUPS-Get-Devices successful-ok
Nov 17 20:01:58 nyx cupsd[1713]: REQUEST localhost - root "POST / HTTP/1.1" 200 173 CUPS-Get-Devices -
Nov 17 20:01:58 nyx cupsd[1713]: REQUEST localhost - root "POST / HTTP/1.1" 200 327 CUPS-Get-Devices -
Nov 17 20:01:58 nyx cupsd[1713]: REQUEST localhost - root "POST / HTTP/1.1" 200 341 CUPS-Get-Devices -
Nov 17 20:01:58 nyx cupsd[1713]: REQUEST localhost - root "POST / HTTP/1.1" 200 323 CUPS-Get-Devices -
Nov 17 20:01:58 nyx cupsd[1713]: REQUEST localhost - root "POST / HTTP/1.1" 200 322 CUPS-Get-Devices -
Nov 17 20:01:58 nyx cupsd[1713]: REQUEST localhost - root "POST / HTTP/1.1" 200 331 CUPS-Get-Devices -
Nov 17 20:01:58 nyx hp[14620]: io/hpmud/pp.c 627: unable to read device-id ret=-1
Nov 17 20:01:58 nyx cupsd[1713]: REQUEST localhost - root "POST / HTTP/1.1" 200 314 CUPS-Get-Devices -
Nov 17 20:01:59 nyx gnome-keyring-daemon[2497]: asked to register item /org/freedesktop/secrets/collection/login/53, but it's already registered
Nov 17 20:01:59 nyx gnome-keyring-daemon[2497]: asked to register item /org/freedesktop/secrets/collection/login/52, but it's already registered
Nov 17 20:02:00 nyx cupsd[1713]: REQUEST localhost - root "POST / HTTP/1.1" 200 859 CUPS-Get-Devices -
Nov 17 20:02:00 nyx systemd[2478]: Started dbus-:1.2-org.fedoraproject.Config.Printing@1.service.
Nov 17 20:02:03 nyx gnome-control-c[7233]: gdkwindow-x11.c:5633 drawable is not a native X11 window
Nov 17 20:02:04 nyx gnome-keyring-daemon[2497]: asked to register item /org/freedesktop/secrets/collection/login/53, but it's already registered
Nov 17 20:02:04 nyx gnome-keyring-daemon[2497]: asked to register item /org/freedesktop/secrets/collection/login/52, but it's already registered
Nov 17 20:02:04 nyx cupsd[1713]: REQUEST localhost - root "POST / HTTP/1.1" 200 1184 CUPS-Get-Devices -
Nov 17 20:02:08 nyx cupsd[1713]: REQUEST localhost - - "POST / HTTP/1.1" 200 6597237 CUPS-Get-PPDs -
Nov 17 20:02:09 nyx gnome-keyring-daemon[2497]: asked to register item /org/freedesktop/secrets/collection/login/53, but it's already registered
Nov 17 20:02:09 nyx gnome-keyring-daemon[2497]: asked to register item /org/freedesktop/secrets/collection/login/52, but it's already registered
Nov 17 20:02:09 nyx gnome-keyring-daemon[2497]: asked to register item /org/freedesktop/secrets/collection/login/52, but it's already registered
Nov 17 20:02:09 nyx cupsd[1713]: [CGI] Cannot connect to remote printer ipp://NPIA997CD.local:631/ipp/print (NPIA997CD.local:631)
Nov 17 20:02:09 nyx cupsd[1713]: copy_model: empty PPD file
Nov 17 20:02:09 nyx cupsd[1713]: [Client 183] Returning IPP server-error-internal-error for CUPS-Add-Modify-Printer (ipp://localhost/printers/HP-ColorLaserJet-MFP-M278-M281) from localhost.
Nov 17 20:02:09 nyx cupsd[1713]: REQUEST localhost - root "POST /admin/ HTTP/1.1" 200 447 CUPS-Add-Modify-Printer server-error-internal-error
Nov 17 20:02:09 nyx gnome-control-c[7233]: cups-pk-helper: addition of printer HP-ColorLaserJet-MFP-M278-M281 failed: server-error-internal-error
Nov 17 20:02:10 nyx gnome-keyring-daemon[2497]: asked to register item /org/freedesktop/secrets/collection/login/53, but it's already registered
Nov 17 20:02:11 nyx gnome-control-c[7233]: Installation of the new printer failed.
Nov 17 20:02:11 nyx gnome-control-c[7233]: gtk_widget_get_allocation: assertion 'GTK_IS_WIDGET (widget)' failed
Nov 17 20:02:11 nyx gnome-control-c[7233]: gtk_widget_get_margin_top: assertion 'GTK_IS_WIDGET (widget)' failed
Nov 17 20:02:11 nyx gnome-control-c[7233]: gtk_widget_draw: assertion '!widget->priv->alloc_needed' failed
Nov 17 20:02:14 nyx gnome-keyring-daemon[2497]: asked to register item /org/freedesktop/secrets/collection/login/53, but it's already registered
Nov 17 20:02:14 nyx gnome-keyring-daemon[2497]: asked to register item /org/freedesktop/secrets/collection/login/52, but it's already registered
Nov 17 20:02:19 nyx gnome-keyring-daemon[2497]: asked to register item /org/freedesktop/secrets/collection/login/53, but it's already registered
Nov 17 20:02:19 nyx gnome-keyring-daemon[2497]: asked to register item /org/freedesktop/secrets/collection/login/52, but it's already registered
Nov 17 20:02:20 nyx gnome-keyring-daemon[2497]: asked to register item /org/freedesktop/secrets/collection/login/53, but it's already registered
Nov 17 20:02:24 nyx gnome-keyring-daemon[2497]: asked to register item /org/freedesktop/secrets/collection/login/53, but it's already registered
Nov 17 20:02:24 nyx gnome-keyring-daemon[2497]: asked to register item /org/freedesktop/secrets/collection/login/52, but it's already registered
Nov 17 20:02:29 nyx gnome-keyring-daemon[2497]: asked to register item /org/freedesktop/secrets/collection/login/53, but it's already registered
Nov 17 20:02:29 nyx gnome-keyring-daemon[2497]: asked to register item /org/freedesktop/secrets/collection/login/52, but it's already registered
Nov 17 20:02:34 nyx gnome-keyring-daemon[2497]: asked to register item /org/freedesktop/secrets/collection/login/53, but it's already registered
Nov 17 20:02:34 nyx gnome-keyring-daemon[2497]: asked to register item /org/freedesktop/secrets/collection/login/52, but it's already registered
Nov 17 20:02:39 nyx gnome-keyring-daemon[2497]: asked to register item /org/freedesktop/secrets/collection/login/53, but it's already registered
Nov 17 20:02:39 nyx gnome-keyring-daemon[2497]: asked to register item /org/freedesktop/secrets/collection/login/52, but it's already registered
Nov 17 20:02:40 nyx scp-dbus-service[14629]: /usr/share/system-config-printer/scp-dbus-service.py:602: DeprecationWarning: Gdk.threads_enter is deprecated
Nov 17 20:02:40 nyx scp-dbus-service[14629]:   Gdk.threads_enter ()
Nov 17 20:02:40 nyx systemd[1]: dbus-:1.5-org.opensuse.CupsPkHelper.Mechanism@2.service: Succeeded.
Nov 17 20:02:40 nyx audit[1]: SERVICE_STOP pid=1 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:init_t:s0 msg='unit=dbus-:1.5-org.opensuse.CupsPkHelper.Mechanism@2 comm="systemd" exe="/usr/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
Nov 17 20:02:40 nyx systemd[2478]: dbus-:1.2-org.fedoraproject.Config.Printing@1.service: Succeeded.
Nov 17 20:02:40 nyx systemd[2478]: dbus-:1.2-org.fedoraproject.Config.Printing@1.service: Consumed 1.990s CPU time.