Not able to see the desktop but only the vncconfig window

[Hsu Jason]

I'm still learning Linux and first time use TigerVNC.  I created a VM on Hyper-V with ubuntu server 20.04 and installed ubuntu-gnome-desktop and tigervnc on port 5901 (-localhost no :1.) on it.  I can use $> startx to start GNOME desktop and see it successfully.  However, when I can only see the small grey window with 4 checkboxes like: Accept clipboard from viewers, etc... by use VNC Viwer, TigerVNC Viewer Java or MobaXterm.

Please advice about where I'm missing.

Here is my ~/.vnc/xstartup

#!/bin/sh

# Start Gnome 3 Desktop
[ -x /etc/vnc/xstartup ] && exec /etc/vnc/xstartup
[ -r $HOME/.Xresources ] && xrdb $HOME/.Xresources
vncconfig -iconic &
dbus-launch --exit-with-session gnome-session &

And in vncserver@.service:

[Unit]

Description=VNC Server by TeknoTut

After=syslog.target network.target

[Service]

Type=forking

User=jason

Group=jason

WorkingDirectory=/home/jason

PIDFile=/home/jason/.vnc/%H:%i.pid

# Clean any existing files in /tmp/.X11-unix environment

ExecStartPre=/usr/bin/vncserver -kill :%i > /dev/null 2>&1 || :

ExecStart=/usr/bin/vncserver -geometry 1600x900 -depth 24 -localhost no :%i

ExecStop=/usr/bin/vncserver -kill :%i

[Install]

WantedBy=multi-user.target