Public bug reported: I work remotely by running an XFCE session inside an X display created by vnc4server. On Ubuntu xenial, this causes xfce4-notifyd to fail to start up.
A transcript of my VNC startup script and the results: simon@xenial:~$ cat ~/.vnc/xstartup #!/bin/sh exec setsid xfce4-session simon@xenial:~$ vncserver :1 New 'xenial:1 (simon)' desktop is xenial:1 Starting applications specified in /home/simon/.vnc/xstartup Log file is /home/simon/.vnc/xenial:1.log simon@xenial:~$ ps xf | grep xfce4-notifyd 4017 pts/0 S+ 0:00 \_ grep --color=auto xfce4-notifyd simon@xenial:~$ systemctl --user status xfce4-notifyd.service ● xfce4-notifyd.service - XFCE notifications service Loaded: loaded (/usr/lib/systemd/user/xfce4-notifyd.service; static; vendor preset: enabled) Active: failed (Result: exit-code) since Wed 2020-10-07 11:29:41 BST; 27s ago Process: 3943 ExecStart=/usr/lib/x86_64-linux-gnu/xfce4/notifyd/xfce4-notifyd (code=exited, status Main PID: 3943 (code=exited, status=1/FAILURE) Oct 07 11:29:41 xenial systemd[3794]: Starting XFCE notifications service... Oct 07 11:29:41 xenial xfce4-notifyd[3943]: Unable to init server: Could not connect: Connection ref Oct 07 11:29:41 xenial xfce4-notifyd[3943]: cannot open display: Oct 07 11:29:41 xenial systemd[3794]: xfce4-notifyd.service: Main process exited, code=exited, statu Oct 07 11:29:41 xenial systemd[3794]: xfce4-notifyd.service: Failed with result 'exit-code'. Oct 07 11:29:41 xenial systemd[3794]: Failed to start XFCE notifications service. simon@xenial:~$ exit If I manually edit /usr/lib/systemd/user/xfce4-notifyd.service so that it adds "--display :1" to the command line, then xfce4-notifyd starts up correctly. (But obviously this is a horrible bodge that I only did temporarily for diagnostic purposes :-) So I conjecture that the X display parameter is somehow not finding its way to xfce4-notifyd during startup, and that in the normal case nobody notices because xfce4-notifyd defaults to trying to connect to :0. System details: this can be reproduced on a clean, freshly installed xubuntu 18.04 system (in a test VM, installed on 2020-10-07). The only configuration I performed was to edit my ~/.vnc/xstartup so that it runs xfce4-session (as shown in the transcript above). simon@xenial:~$ lsb_release -rd Description: Ubuntu 18.04 LTS Release: 18.04 simon@xenial:~$ apt-cache policy xfce4-notifyd xfce4-notifyd: Installed: 0.4.2-0ubuntu2 Candidate: 0.4.2-0ubuntu2 Version table: *** 0.4.2-0ubuntu2 500 500 http://gb.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages 100 /var/lib/dpkg/status ** Affects: xfce4-notifyd (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1898858 Title: xfce4-notifyd fails to start on displays other than :0 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xfce4-notifyd/+bug/1898858/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs