Échec du démarrage du service serveur TigerVNC

Essayer d'installer TigerVNC pour un accès dektop distant (en tant que root) sur une machine centos7, basé sur cet article . Avoir les configs

[root@HW01 ~]# cat /etc/systemd/system/vncserver@:1.service
# The vncserver service unit file
#
# Quick HowTo:
# 1. Copy this file to /etc/systemd/system/vncserver@.service
# 2. Replace <USER> with the actual user name and edit vncserver
#    parameters appropriately
#    (ExecStart=/usr/sbin/runuser -l <USER> -c "/usr/bin/vncserver %i"
#     PIDFile=/home/<USER>/.vnc/%H%i.pid)
# 3. Run `systemctl daemon-reload`
# 4. Run `systemctl enable vncserver@:<display>.service`
#
# DO NOT RUN THIS SERVICE if your local area network is
# untrusted!  For a secure way of using VNC, you should
# limit connections to the local host and then tunnel from
# the machine you want to view VNC on (host A) to the machine
# whose VNC output you want to view (host B)
#
# [user@hostA ~]$ ssh -v -C -L 590N:localhost:590M hostB
#
# this will open a connection on port 590N of your hostA to hostB's port 590M
# (in fact, it ssh-connects to hostB and then connects to localhost (on hostB).
# See the ssh man page for details on port forwarding)
#
# You can then point a VNC client on hostA at vncdisplay N of localhost and with
# the help of ssh, you end up seeing what hostB makes available on port 590M
#
# Use "-nolisten tcp" to prevent X connections to your VNC server via TCP.
#
# Use "-localhost" to prevent remote VNC clients connecting except when
# doing so through a secure tunnel.  See the "-via" option in the
# `man vncviewer' manual page.


[Unit]
Description=Remote desktop service (VNC)
After=syslog.target network.target

[Service]
Type=forking

# Clean any existing files in /tmp/.X11-unix environment
ExecStartPre=/bin/sh -c '/usr/bin/vncserver -kill %i > /dev/null 2>&1 || :'
ExecStart=/usr/sbin/runuser -l root -c "/usr/bin/vncserver %i"
PIDFile=/root/.vnc/%H%i.pid
ExecStop=/bin/sh -c '/usr/bin/vncserver -kill %i > /dev/null 2>&1 || :'

[Install]
WantedBy=multi-user.target

L'a fait...

[root@HW01 ~]# vncpasswd
Password:
Password not changed
[root@HW01 ~]#

Pour confirmer aucun mot de passe pour root, mais j'obtiens les erreurs suivantes...

[root@HW01 ~]# systemctl start vncserver@:1.service
Job for vncserver@:1.service failed because the control process exited with error code. See "systemctl status vncserver@:1.service" and "journalctl -xe" for details.
[root@HW01 ~]# systemctl status vncserver@:1.service
● vncserver@:1.service - Remote desktop service (VNC)
   Loaded: loaded (/etc/systemd/system/vncserver@:1.service; enabled; vendor preset: disabled)
   Active: failed (Result: exit-code) since Fri 2019-07-19 16:03:11 HST; 14s ago
  Process: 72135 ExecStart=/usr/sbin/runuser -l root -c /usr/bin/vncserver %i (code=exited, status=1/FAILURE)
  Process: 72129 ExecStartPre=/bin/sh -c /usr/bin/vncserver -kill %i > /dev/null 2>&1 || : (code=exited, status=0/SUCCESS)

Jul 19 16:03:11 HW01.ucera.local systemd[1]: Starting Remote desktop service (VNC)...
Jul 19 16:03:11 HW01.co.local runuser[72135]: Password:
Jul 19 16:03:11 HW01.co.local systemd[1]: vncserver@:1.service: control process exited, cod...s=1
Jul 19 16:03:11 HW01.co.local systemd[1]: Failed to start Remote desktop service (VNC).
Jul 19 16:03:11 HW01.co.local systemd[1]: Unit vncserver@:1.service entered failed state.
Jul 19 16:03:11 HW01.co.local systemd[1]: vncserver@:1.service failed.
Hint: Some lines were ellipsized, use -l to show in full.

Quelqu'un sait ce qui pourrait mal se passer ici ? Des suggestions de débogage?