I see this on Ubuntu 18.04 as well, but I have a gnome-based gui that works. Here's my log snippet:
May 26 12:23:47 cerberus org.gnome.ScreenSaver[2217]: Unable to init server: Could not connect: Connection refused May 26 12:23:47 cerberus gnome-screensav[2263]: Cannot open display: May 26 12:23:47 cerberus dbus-daemon[2217]: [session uid=130 pid=2217] Activated service 'org.gnome.ScreenSaver' failed: Process org.gnome.ScreenSaver exited with status 1 May 26 12:23:47 cerberus gnome-session[2223]: gnome-session-binary[2223]: CRITICAL: Unable to create a DBus proxy for GnomeScreensaver: Error calling StartServiceByName for org.gnome.ScreenSav May 26 12:23:47 cerberus gnome-session-binary[2223]: CRITICAL: Unable to create a DBus proxy for GnomeScreensaver: Error calling StartServiceByName for org.gnome.ScreenSaver: GDBus.Error:org.f -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to gnome-screensaver in Ubuntu. https://bugs.launchpad.net/bugs/1716639 Title: gnome-screensaver issue when using Wayland Status in gnome-screensaver package in Ubuntu: Confirmed Bug description: When using a Wayland session instead of X11 from the standard lightdm- gtk-greeter, apparently gnome-screensaver cannot establish proper GTK+ initialisation, causing the gnome-session-binary to exit and subsequently a greeter loop where a user is unable to log in. The following is an excerpt from the syslog: ep 12 11:06:49 darkstar-xps dbus-daemon[2031]: Activating service name='org.gnome.ScreenSaver' Sep 12 11:06:49 darkstar-xps org.gnome.ScreenSaver[2031]: Unable to init server: Could not connect: Connection refused Sep 12 11:06:49 darkstar-xps gnome-screensav[2165]: Unable to initialize GTK+ S Running an identical session without Wayland produces the expected behaviour: a user can log into his desktop session and start working as usual. Removing org.gnome.SettingsDaemon.ScreensaverProxy from /usr/share /gnome-session/sessions/gnome.session doesn't have any effect. I'm suspecting foul play between the screensaver proxy and the screensaver binary itself, but don't have the bandwidth to analyse the source at the moment. More than happy to provide more information as required - just let me know. ProblemType: Bug DistroRelease: Ubuntu 17.04 Package: gnome-screensaver 3.6.1-7ubuntu5 ProcVersionSignature: Ubuntu 4.10.0-33.37-generic 4.10.17 Uname: Linux 4.10.0-33-generic x86_64 ApportVersion: 2.20.4-0ubuntu4.5 Architecture: amd64 CurrentDesktop: GNOME Date: Tue Sep 12 11:29:30 2017 GnomeSessionIdleInhibited: No GnomeSessionInhibitors: None GsettingsGnomeSession: org.gnome.desktop.session session-name 'ubuntu' org.gnome.desktop.session idle-delay uint32 300 InstallationDate: Installed on 2017-08-31 (11 days ago) InstallationMedia: Ubuntu 17.04 "Zesty Zapus" - Release amd64 (20170412) SourcePackage: gnome-screensaver UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-screensaver/+bug/1716639/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
