XDMCP does not work on Raspi Groovy while it works fine on Groovy Ubuntu Mate AMD64

[Ryutaroh Matsumoto]

The following configuration enables XDMCP of LightDM in Ubuntu Mate Groovy.
But it fails on Groovy Raspberry Pi 64bit.

[LightDM]
start-default-seat=false
lock-memory=false
remote-sessions-directory=/usr/share/lightdm/sessions:/usr/share/xsessions:/usr/share/wayland-sessions
[XDMCPServer]
enabled=true
#port=177
listen-address=127.0.0.1

journalctl -e shows the following:

Oct 26 07:56:41 raspi-groovy systemd[1]: Started Session 1 of user root.
Oct 26 07:57:10 raspi-groovy systemd[1]: /etc/systemd/system/Xtigervnc@.service:9: Special user nobody configured, this is not safe!
Oct 26 07:57:10 raspi-groovy systemd[1]: Created slice system-Xtigervnc.slice.
Oct 26 07:57:10 raspi-groovy systemd[1]: Starting XVNC Per-Connection Daemon (192.168.1.75:41812)...
Oct 26 07:57:10 raspi-groovy systemd[1]: Started XVNC Per-Connection Daemon (192.168.1.75:41812).
Oct 26 07:57:11 raspi-groovy lightdm[893]: PAM unable to dlopen(pam_kwallet.so): /lib/security/pam_kwallet.so: cannot open shared object file: No such file or directory
Oct 26 07:57:11 raspi-groovy lightdm[893]: PAM adding faulty module: pam_kwallet.so
Oct 26 07:57:11 raspi-groovy lightdm[893]: PAM unable to dlopen(pam_kwallet5.so): /lib/security/pam_kwallet5.so: cannot open shared object file: No such file or directory
Oct 26 07:57:11 raspi-groovy lightdm[893]: PAM adding faulty module: pam_kwallet5.so
Oct 26 07:57:11 raspi-groovy lightdm[893]: pam_unix(lightdm-greeter:session): session opened for user lightdm by (uid=0)
Oct 26 07:57:11 raspi-groovy systemd[1]: Created slice User Slice of UID 108.
Oct 26 07:57:11 raspi-groovy systemd[1]: Starting User Runtime Directory /run/user/108...
Oct 26 07:57:11 raspi-groovy systemd-logind[530]: New session c1 of user lightdm.
Oct 26 07:57:11 raspi-groovy systemd[1]: Finished User Runtime Directory /run/user/108.
Oct 26 07:57:11 raspi-groovy systemd[1]: Starting User Manager for UID 108...
Oct 26 07:57:11 raspi-groovy systemd[897]: pam_unix(systemd-user:session): session opened for user lightdm by (uid=0)
Oct 26 07:57:12 raspi-groovy systemd[902]: gnome-systemd-autostart-condition not found: No such file or directory
Oct 26 07:57:12 raspi-groovy systemd[902]: Not generating service for XDG autostart app-org.gnome.SettingsDaemon.PrintNotifications-autostart.service, startup phases are not supported.
Oct 26 07:57:12 raspi-groovy systemd[902]: Not generating service for XDG autostart app-gnome\x2dinitial\x2dsetup\x2dcopy\x2dworker-autostart.service, startup phases are not supported.
Oct 26 07:57:12 raspi-groovy systemd[902]: Not generating service for XDG autostart app-org.gnome.SettingsDaemon.MediaKeys-autostart.service, startup phases are not supported.
Oct 26 07:57:12 raspi-groovy systemd[902]: Not generating service for XDG autostart app-org.gnome.SettingsDaemon.Smartcard-autostart.service, startup phases are not supported.
Oct 26 07:57:12 raspi-groovy systemd[902]: Not generating service for XDG autostart app-gnome\x2dkeyring\x2dsecrets-autostart.service, startup phases are not supported.
Oct 26 07:57:12 raspi-groovy systemd[902]: Not generating service for XDG autostart app-at\x2dspi\x2ddbus\x2dbus-autostart.service, startup phases are not supported.
Oct 26 07:57:12 raspi-groovy systemd[902]: Not generating service for XDG autostart app-org.gnome.SettingsDaemon.Housekeeping-autostart.service, startup phases are not supported.
Oct 26 07:57:12 raspi-groovy systemd[902]: gnome-systemd-autostart-condition not found: No such file or directory
Oct 26 07:57:12 raspi-groovy systemd[902]: gnome-systemd-autostart-condition not found: No such file or directory
Oct 26 07:57:12 raspi-groovy systemd[902]: Not generating service for XDG autostart app-gnome\x2dkeyring\x2dssh-autostart.service, startup phases are not supported.
Oct 26 07:57:12 raspi-groovy systemd[902]: Not generating service for XDG autostart app-org.gnome.SettingsDaemon.Color-autostart.service, startup phases are not supported.
Oct 26 07:57:12 raspi-groovy systemd[902]: Not generating service for XDG autostart app-org.gnome.SettingsDaemon.Wwan-autostart.service, startup phases are not supported.
Oct 26 07:57:12 raspi-groovy systemd[902]: Not generating service for XDG autostart app-xdg\x2duser\x2ddirs-autostart.service, startup phases are not supported.
Oct 26 07:57:12 raspi-groovy systemd[902]: Not generating service for XDG autostart app-pulseaudio-autostart.service, startup phases are not supported.
Oct 26 07:57:12 raspi-groovy systemd[902]: Not generating service for XDG autostart app-org.gnome.SettingsDaemon.Rfkill-autostart.service, startup phases are not supported.
Oct 26 07:57:12 raspi-groovy systemd[902]: Not generating service for XDG autostart app-gnome\x2dkeyring\x2dpkcs11-autostart.service, startup phases are not supported.
Oct 26 07:57:12 raspi-groovy systemd[902]: Not generating service for XDG autostart app-org.gnome.SettingsDaemon.A11ySettings-autostart.service, startup phases are not supported.
Oct 26 07:57:12 raspi-groovy systemd[902]: Not generating service for XDG autostart app-org.gnome.SettingsDaemon.XSettings-autostart.service, startup phases are not supported.
Oct 26 07:57:12 raspi-groovy systemd[902]: Not generating service for XDG autostart app-org.gnome.SettingsDaemon.ScreensaverProxy-autostart.service, startup phases are not supported.
Oct 26 07:57:12 raspi-groovy systemd[902]: Not generating service for XDG autostart app-org.gnome.SettingsDaemon.Datetime-autostart.service, startup phases are not supported.
Oct 26 07:57:12 raspi-groovy systemd[902]: Not generating service for XDG autostart app-org.gnome.SettingsDaemon.Sound-autostart.service, startup phases are not supported.
Oct 26 07:57:12 raspi-groovy systemd[902]: Not generating service for XDG autostart app-org.gnome.SettingsDaemon.Keyboard-autostart.service, startup phases are not supported.
Oct 26 07:57:12 raspi-groovy systemd[902]: Not generating service for XDG autostart app-org.gnome.SettingsDaemon.UsbProtection-autostart.service, startup phases are not supported.
Oct 26 07:57:12 raspi-groovy systemd[902]: Not generating service for XDG autostart app-spice\x2dvdagent-autostart.service, startup phases are not supported.
Oct 26 07:57:12 raspi-groovy systemd[902]: Not generating service for XDG autostart app-org.gnome.SettingsDaemon.Sharing-autostart.service, startup phases are not supported.
Oct 26 07:57:12 raspi-groovy systemd[902]: Not generating service for XDG autostart app-org.gnome.SettingsDaemon.Wacom-autostart.service, startup phases are not supported.
Oct 26 07:57:12 raspi-groovy systemd[902]: Not generating service for XDG autostart app-org.gnome.SettingsDaemon.Power-autostart.service, startup phases are not supported.
Oct 26 07:57:12 raspi-groovy systemd[897]: Queued start job for default target Main User Target.
Oct 26 07:57:12 raspi-groovy systemd[897]: Started Pending report trigger for Ubuntu Report.
Oct 26 07:57:12 raspi-groovy systemd[897]: Reached target Paths.
Oct 26 07:57:12 raspi-groovy systemd[897]: Reached target Timers.
Oct 26 07:57:12 raspi-groovy systemd[897]: Starting D-Bus User Message Bus Socket.
Oct 26 07:57:12 raspi-groovy systemd[897]: Listening on GnuPG network certificate management daemon.
Oct 26 07:57:12 raspi-groovy systemd[897]: Listening on GnuPG cryptographic agent and passphrase cache (access for web browsers).
Oct 26 07:57:12 raspi-groovy systemd[897]: Listening on GnuPG cryptographic agent and passphrase cache (restricted).
Oct 26 07:57:12 raspi-groovy systemd[897]: Listening on GnuPG cryptographic agent (ssh-agent emulation).
Oct 26 07:57:12 raspi-groovy systemd[897]: Listening on GnuPG cryptographic agent and passphrase cache.
Oct 26 07:57:12 raspi-groovy systemd[897]: Listening on debconf communication socket.
Oct 26 07:57:12 raspi-groovy systemd[897]: Listening on Sound System.
Oct 26 07:57:12 raspi-groovy systemd[897]: Listening on D-Bus User Message Bus Socket.
Oct 26 07:57:12 raspi-groovy systemd[897]: Reached target Sockets.
Oct 26 07:57:12 raspi-groovy systemd[897]: Reached target Basic System.
Oct 26 07:57:12 raspi-groovy systemd[1]: Started User Manager for UID 108.
Oct 26 07:57:12 raspi-groovy systemd[897]: Starting Sound Service...
Oct 26 07:57:12 raspi-groovy systemd[1]: Started Session c1 of user lightdm.
Oct 26 07:57:12 raspi-groovy systemd[897]: Starting Tracker metadata extractor...
Oct 26 07:57:12 raspi-groovy systemd[897]: Starting Tracker file system data miner...
Oct 26 07:57:12 raspi-groovy lightdm[893]: gkr-pam: gnome-keyring-daemon started properly
Oct 26 07:57:12 raspi-groovy lightdm[649]: Error activating login1 session: GDBus.Error:org.freedesktop.DBus.Error.NotSupported: Operation not supported
Oct 26 07:57:13 raspi-groovy tracker-miner-f[906]: Set scheduler policy to SCHED_IDLE
Oct 26 07:57:13 raspi-groovy tracker-extract[905]: Set scheduler policy to SCHED_IDLE
Oct 26 07:57:13 raspi-groovy tracker-extract[905]: Setting priority nice level to 19
Oct 26 07:57:13 raspi-groovy tracker-miner-f[906]: Setting priority nice level to 19
Oct 26 07:57:13 raspi-groovy systemd[897]: Started D-Bus User Message Bus.
Oct 26 07:57:13 raspi-groovy dbus-daemon[915]: [session uid=108 pid=915] AppArmor D-Bus mediation is enabled
Oct 26 07:57:13 raspi-groovy dbus-daemon[915]: [session uid=108 pid=915] Activating via systemd: service name='org.gtk.vfs.Daemon' unit='gvfs-daemon.service' requested by ':1.1' (uid=108 pid=906 comm="/usr/libexec/tracker-miner-fs " label="unconfined")
Oct 26 07:57:13 raspi-groovy systemd[897]: Starting Virtual filesystem service...
Oct 26 07:57:13 raspi-groovy systemd[897]: Started Sound Service.
Oct 26 07:57:13 raspi-groovy bluetoothd[578]: Endpoint registered: sender=:1.54 path=/MediaEndpoint/A2DPSink/sbc
Oct 26 07:57:13 raspi-groovy bluetoothd[578]: Endpoint registered: sender=:1.54 path=/MediaEndpoint/A2DPSource/sbc
Oct 26 07:57:13 raspi-groovy kernel: Bluetooth: RFCOMM TTY layer initialized
Oct 26 07:57:13 raspi-groovy kernel: Bluetooth: RFCOMM socket layer initialized
Oct 26 07:57:13 raspi-groovy kernel: Bluetooth: RFCOMM ver 1.11
Oct 26 07:57:13 raspi-groovy dbus-daemon[915]: [session uid=108 pid=915] Successfully activated service 'org.gtk.vfs.Daemon'
Oct 26 07:57:13 raspi-groovy systemd[897]: Started Virtual filesystem service.
Oct 26 07:57:13 raspi-groovy tracker-miner-f[906]: Unable to get XDG user directory path for special directory &DOCUMENTS. Ignoring this location.
Oct 26 07:57:13 raspi-groovy tracker-miner-f[906]: Unable to get XDG user directory path for special directory &MUSIC. Ignoring this location.
Oct 26 07:57:13 raspi-groovy tracker-miner-f[906]: Unable to get XDG user directory path for special directory &PICTURES. Ignoring this location.
Oct 26 07:57:13 raspi-groovy tracker-miner-f[906]: Unable to get XDG user directory path for special directory &VIDEOS. Ignoring this location.
Oct 26 07:57:13 raspi-groovy tracker-miner-f[906]: Unable to get XDG user directory path for special directory &DOWNLOAD. Ignoring this location.
Oct 26 07:57:13 raspi-groovy tracker-miner-f[906]: Unable to get XDG user directory path for special directory &DOCUMENTS. Ignoring this location.
Oct 26 07:57:13 raspi-groovy tracker-miner-f[906]: Unable to get XDG user directory path for special directory &MUSIC. Ignoring this location.
Oct 26 07:57:13 raspi-groovy tracker-miner-f[906]: Unable to get XDG user directory path for special directory &PICTURES. Ignoring this location.
Oct 26 07:57:13 raspi-groovy tracker-miner-f[906]: Unable to get XDG user directory path for special directory &VIDEOS. Ignoring this location.
Oct 26 07:57:13 raspi-groovy dbus-daemon[915]: [session uid=108 pid=915] Activating via systemd: service name='org.gtk.vfs.UDisks2VolumeMonitor' unit='gvfs-udisks2-volume-monitor.service' requested by ':1.1' (uid=108 pid=906 comm="/usr/libexec/tracker-miner-fs " label="unconfined")
Oct 26 07:57:13 raspi-groovy systemd[897]: Starting Virtual filesystem service - disk device monitor...
Oct 26 07:57:13 raspi-groovy dbus-daemon[915]: [session uid=108 pid=915] Successfully activated service 'org.gtk.vfs.UDisks2VolumeMonitor'
Oct 26 07:57:13 raspi-groovy systemd[897]: Started Virtual filesystem service - disk device monitor.
Oct 26 07:57:13 raspi-groovy dbus-daemon[915]: [session uid=108 pid=915] Activating via systemd: service name='org.gtk.vfs.AfcVolumeMonitor' unit='gvfs-afc-volume-monitor.service' requested by ':1.1' (uid=108 pid=906 comm="/usr/libexec/tracker-miner-fs " label="unconfined")
Oct 26 07:57:13 raspi-groovy systemd[897]: Starting Virtual filesystem service - Apple File Conduit monitor...
Oct 26 07:57:14 raspi-groovy dbus-daemon[915]: [session uid=108 pid=915] Successfully activated service 'org.gtk.vfs.AfcVolumeMonitor'
Oct 26 07:57:14 raspi-groovy systemd[897]: Started Virtual filesystem service - Apple File Conduit monitor.
Oct 26 07:57:14 raspi-groovy dbus-daemon[915]: [session uid=108 pid=915] Activating via systemd: service name='org.gtk.vfs.GPhoto2VolumeMonitor' unit='gvfs-gphoto2-volume-monitor.service' requested by ':1.1' (uid=108 pid=906 comm="/usr/libexec/tracker-miner-fs " label="unconfined")
Oct 26 07:57:14 raspi-groovy systemd[897]: Starting Virtual filesystem service - digital camera monitor...
Oct 26 07:57:14 raspi-groovy dbus-daemon[915]: [session uid=108 pid=915] Successfully activated service 'org.gtk.vfs.GPhoto2VolumeMonitor'
Oct 26 07:57:14 raspi-groovy systemd[897]: Started Virtual filesystem service - digital camera monitor.
Oct 26 07:57:14 raspi-groovy dbus-daemon[915]: [session uid=108 pid=915] Activating via systemd: service name='org.gtk.vfs.GoaVolumeMonitor' unit='gvfs-goa-volume-monitor.service' requested by ':1.1' (uid=108 pid=906 comm="/usr/libexec/tracker-miner-fs " label="unconfined")
Oct 26 07:57:14 raspi-groovy systemd[897]: Starting Virtual filesystem service - GNOME Online Accounts monitor...
Oct 26 07:57:14 raspi-groovy dbus-daemon[915]: [session uid=108 pid=915] Activating service name='org.gnome.OnlineAccounts' requested by ':1.9' (uid=108 pid=962 comm="/usr/libexec/gvfs-goa-volume-monitor " label="unconfined")
Oct 26 07:57:15 raspi-groovy goa-daemon[966]: goa-daemon version 3.37.90 starting
Oct 26 07:57:15 raspi-groovy dbus-daemon[915]: [session uid=108 pid=915] Activating service name='org.gnome.Identity' requested by ':1.10' (uid=108 pid=966 comm="/usr/libexec/goa-daemon " label="unconfined")
Oct 26 07:57:15 raspi-groovy dbus-daemon[915]: [session uid=108 pid=915] Successfully activated service 'org.gnome.OnlineAccounts'
Oct 26 07:57:15 raspi-groovy dbus-daemon[915]: [session uid=108 pid=915] Successfully activated service 'org.gtk.vfs.GoaVolumeMonitor'
Oct 26 07:57:15 raspi-groovy systemd[897]: Started Virtual filesystem service - GNOME Online Accounts monitor.
Oct 26 07:57:15 raspi-groovy dbus-daemon[915]: [session uid=108 pid=915] Successfully activated service 'org.gnome.Identity'
Oct 26 07:57:15 raspi-groovy dbus-daemon[915]: [session uid=108 pid=915] Activating via systemd: service name='org.gtk.vfs.MTPVolumeMonitor' unit='gvfs-mtp-volume-monitor.service' requested by ':1.1' (uid=108 pid=906 comm="/usr/libexec/tracker-miner-fs " label="unconfined")
Oct 26 07:57:15 raspi-groovy systemd[897]: Starting Virtual filesystem service - Media Transfer Protocol monitor...
Oct 26 07:57:15 raspi-groovy dbus-daemon[915]: [session uid=108 pid=915] Successfully activated service 'org.gtk.vfs.MTPVolumeMonitor'
Oct 26 07:57:15 raspi-groovy systemd[897]: Started Virtual filesystem service - Media Transfer Protocol monitor.
Oct 26 07:57:15 raspi-groovy dbus-daemon[510]: [system] Activating via systemd: service name='org.freedesktop.UPower' unit='upower.service' requested by ':1.62' (uid=108 pid=906 comm="/usr/libexec/tracker-miner-fs " label="unconfined")
Oct 26 07:57:15 raspi-groovy systemd[1]: Starting Daemon for power management...
Oct 26 07:57:15 raspi-groovy systemd[897]: Started Tracker metadata extractor.
Oct 26 07:57:15 raspi-groovy dbus-daemon[510]: [system] Successfully activated service 'org.freedesktop.UPower'
Oct 26 07:57:15 raspi-groovy systemd[1]: Started Daemon for power management.
Oct 26 07:57:15 raspi-groovy dbus-daemon[915]: [session uid=108 pid=915] Activating via systemd: service name='org.freedesktop.Tracker1' unit='tracker-store.service' requested by ':1.1' (uid=108 pid=906 comm="/usr/libexec/tracker-miner-fs " label="unconfined")
Oct 26 07:57:15 raspi-groovy systemd[897]: Starting Tracker metadata database store and lookup manager...
Oct 26 07:57:16 raspi-groovy dbus-daemon[915]: [session uid=108 pid=915] Successfully activated service 'org.freedesktop.Tracker1'
Oct 26 07:57:16 raspi-groovy systemd[897]: Started Tracker metadata database store and lookup manager.
Oct 26 07:57:17 raspi-groovy dbus-daemon[915]: [session uid=108 pid=915] Activating via systemd: service name='org.a11y.Bus' unit='at-spi-dbus-bus.service' requested by ':1.14' (uid=108 pid=913 comm="/usr/sbin/lightdm-gtk-greeter " label="unconfined")
Oct 26 07:57:17 raspi-groovy systemd[897]: Starting Accessibility services bus...
Oct 26 07:57:17 raspi-groovy dbus-daemon[915]: [session uid=108 pid=915] Successfully activated service 'org.a11y.Bus'
Oct 26 07:57:17 raspi-groovy systemd[897]: Started Accessibility services bus.
Oct 26 07:57:17 raspi-groovy systemd[897]: Started Tracker file system data miner.
Oct 26 07:57:17 raspi-groovy systemd[897]: Reached target Main User Target.
Oct 26 07:57:17 raspi-groovy systemd[897]: Startup finished in 5.773s.
Oct 26 07:57:18 raspi-groovy lightdm[893]: pam_unix(lightdm-greeter:session): session closed for user lightdm
Oct 26 07:57:18 raspi-groovy lightdm[649]: instance with invalid (NULL) class pointer
Oct 26 07:57:18 raspi-groovy lightdm[649]: g_signal_emit_valist: assertion 'G_TYPE_CHECK_INSTANCE (instance)' failed
Oct 26 07:57:18 raspi-groovy systemd-logind[530]: Session c1 logged out. Waiting for processes to exit.
Oct 26 07:57:18 raspi-groovy bluetoothd[578]: Endpoint unregistered: sender=:1.54 path=/MediaEndpoint/A2DPSink/sbc
Oct 26 07:57:18 raspi-groovy bluetoothd[578]: Endpoint unregistered: sender=:1.54 path=/MediaEndpoint/A2DPSource/sbc
Oct 26 07:57:18 raspi-groovy systemd[897]: pulseaudio.service: Succeeded.
Oct 26 07:57:18 raspi-groovy systemd[1]: Xtigervnc@0-192.168.1.83:5901-192.168.1.75:41812.service: Succeeded.
Oct 26 07:57:18 raspi-groovy dbus-daemon[915]: [session uid=108 pid=915] Activating via systemd: service name='org.gtk.vfs.Metadata' unit='gvfs-metadata.service' requested by ':1.2' (uid=108 pid=905 comm="/usr/libexec/tracker-extract " label="unconfined")
Oct 26 07:57:18 raspi-groovy systemd[897]: Starting Virtual filesystem metadata service...
Oct 26 07:57:18 raspi-groovy dbus-daemon[915]: [session uid=108 pid=915] Successfully activated service 'org.gtk.vfs.Metadata'
Oct 26 07:57:18 raspi-groovy systemd[897]: Started Virtual filesystem metadata service.
Oct 26 07:57:30 raspi-groovy systemd[897]: tracker-extract.service: Succeeded.
Oct 26 07:57:30 raspi-groovy systemd[897]: tracker-extract.service: Consumed 1.103s CPU time.