Gnome session issues:

Apr  9 17:02:55 rfc1178-01 systemd[1]: Cannot add dependency job for unit sys-kernel-security.mount, ignoring: Unit sys-kernel-security.mount failed to load: Invalid argument. See system logs and 'systemctl status sys-kernel-security.mount' for details.
Apr  9 17:02:55 rfc1178-01 systemd[1]: Stopping Remote desktop service (VNC)…
Apr  9 17:02:55 rfc1178-01 gnome-session[2885]: gnome-session[2885]: Gdk-WARNING: gnome-session: Fatal IO error 11 (Resource temporarily unavailable) on X server :1.
Apr  9 17:02:55 rfc1178-01 gnome-session[2885]: Gdk-WARNING: gnome-session: Fatal IO error 11 (Resource temporarily unavailable) on X server :1.
Apr  9 17:02:55 rfc1178-01 gnome-session[2885]: (gnome-session-failed:2915): Gdk-WARNING **: gnome-session-failed: Fatal IO error 11 (Resource temporarily unavailable) on X server :1.
Apr  9 17:02:55 rfc1178-01 systemd[1]: Starting Remote desktop service (VNC)…
Apr  9 17:02:55 rfc1178-01 runuser[2941]: Set Bell volume to 'mute' (0).
Apr  9 17:02:55 rfc1178-01 runuser[2941]: xset:  unable to open display ""
Apr  9 17:02:58 rfc1178-01 runuser[2941]: New 'rfc1178-01:1 (root)' desktop is rfc1178-01:1
Apr  9 17:02:58 rfc1178-01 runuser[2941]: Starting applications specified in /root/.vnc/xstartup
Apr  9 17:02:58 rfc1178-01 runuser[2941]: Log file is /root/.vnc/rfc1178-01:1.log
Apr  9 17:02:58 rfc1178-01 systemd[1]: Started Remote desktop service (VNC).
Apr  9 17:02:58 rfc1178-01 gnome-session[2995]: gnome-session[2995]: WARNING: Unable to find required component 'gnome-shell'
Apr  9 17:02:59 rfc1178-01 gnome-session[2995]: WARNING: Unable to find required component 'gnome-shell'
Apr  9 17:02:59 rfc1178-01 gnome-session[2995]: Entering running state
Apr  9 17:02:59 rfc1178-01 gnome-session[2995]: Fontconfig warning: "/etc/fonts/conf.d/50-user.conf", line 14: reading configurations from ~/.fonts.conf is deprecated.

Fix by installing missing components:

# yum install gnome-shell.i686

Restart the VNC server:

# systemctl restart vncserver@:1

HTH,