TigerVNC throws error on Ubuntu 20.04 on a Raspberry pi 3

I'm trying to run a VNC server on my Raspberry Pi 3 which is running Ubuntu 20.04.2, but the logs ~/.vnc/pi2\:1.log show the following error:

 vncext: VNC extension running! vncext: Listening for VNC connections on all interface(s), port 5901 vncext: created VNC server for screen 0
/usr/bin/startxfce4: X server already running on display :1
gpg-agent[7314]: WARNING: "--write-env-file" is an obsolete option - it has no effect
gpg-agent: a gpg-agent is already running - not starting a new one
(xfce4-session:7250): xfce4-session-WARNING **: 02:52:36.416: gpg-agent returned no PID in the variables
(xfce4-session:7250): xfce4-session-WARNING **: 02:52:36.432: xfsm_manager_load_session: Something wrong with /root/.cache/sessions/xfce4-session-pi2:1, Does it exist? Permissions issue?
(xfwm4:7316): xfwm4-WARNING **: 02:52:38.147: Unsupported GL renderer (llvmpipe (LLVM 12.0.0, 128 bits)).
** (xiccd:7374): WARNING **: 02:52:40.770: EDID is empty
** (wrapper-2.0:7356): WARNING **: 02:52:40.873: No outputs have backlight property
Connection failure: Connection refused
pa_context_connect() failed: Connection refused
** (xiccd:7374): CRITICAL **: 02:52:41.175: device 'xrandr-default' does not exist
(wrapper-2.0:7357): GLib-GIO-CRITICAL **: 02:52:41.205: g_file_new_for_path: assertion 'path != NULL' failed
(wrapper-2.0:7357): GLib-GIO-CRITICAL **: 02:52:41.225: g_file_monitor_file: assertion 'G_IS_FILE (file)' failed
(wrapper-2.0:7357): GLib-GObject-WARNING **: 02:52:41.260: invalid (NULL) pointer instance
(wrapper-2.0:7357): GLib-GObject-CRITICAL **: 02:52:41.263: g_signal_connect_data: assertion 'G_TYPE_CHECK_INSTANCE (instance)' failed
(wrapper-2.0:7357): Gtk-WARNING **: 02:52:41.266: Attempting to add a widget with type GtkToggleButton to a container of type XfcePanelPlugin, but the widget is already inside a container of type XfcePanelPlugin, please remove the widget from its existing container first.
(wrapper-2.0:7357): Gtk-WARNING **: 02:52:41.835: Negative content width -3 (allocation 1, extents 2x2) while allocating gadget (node button, owner GtkToggleButton)
** (light-locker:7410): ERROR **: 02:52:42.114: Environment variable XDG_SESSION_PATH not set. Is LightDM running?
(wrapper-2.0:7356): Gtk-WARNING **: 02:52:42.207: Negative content width -3 (allocation 1, extents 2x2) while allocating gadget (node button, owner PowerManagerButton)
(wrapper-2.0:7358): Gtk-WARNING **: 02:52:42.381: Negative content width -1 (allocation 1, extents 1x1) while allocating gadget (node button, owner XfceArrowButton)
(wrapper-2.0:7355): Gtk-WARNING **: 02:52:42.473: Negative content width -3 (allocation 1, extents 2x2) while allocating gadget (node button, owner PulseaudioButton)
(nm-applet:7370): Gdk-CRITICAL **: 02:52:42.598: gdk_window_thaw_toplevel_updates: assertion 'window->update_and_descendants_freeze_count > 0' failed

I attempted to follow the steps on this tutorial which are as follows:

1. sudo apt update
2. sudo apt install xfce4 xfce4-goodies
3. sudo apt install tigervnc-standalone-server
4. vncpasswd (configure VNC password)
5. Edit ~/.vnc/xstartup with the following:

#!/bin/sh
unset SESSION_MANAGER
unset DBUS_SESSION_BUS_ADDRESS
exec startxfce4 

6. chmod u+x ~/.vnc/xstartup

7. vncserver -localhost no :1

Know someone who can answer? Share a link to this question via email, Twitter, or Facebook.