Debian – vnc gray screen on debian 10 gnome 3

I describe what I exactly did :

First , I installed debian10-netinstall.

Then I installed Gnome via 'Tasksel' command.

Then I used this Tutorial for installing vnc server.
Then I start vncserver via this command tightvncserver -geometry 1024x720 :1 and here is the output :

New 'X' desktop is debian:1

Starting applications specified in /home/parsa/.vnc/xstartup
Log file is /home/parsa/.vnc/debian:1.log

And here is the ~/.vnc/debian:1.log :

parsa@debian:~$ tail -f .vnc/debian\:1.log
26/09/19 11:41:12 Xvnc version TightVNC-1.3.9
26/09/19 11:41:12 Copyright (C) 2000-2007 TightVNC Group
26/09/19 11:41:12 Copyright (C) 1999 AT&T Laboratories Cambridge
26/09/19 11:41:12 All Rights Reserved.
26/09/19 11:41:12 See http://www.tightvnc.com/ for information on TightVNC
26/09/19 11:41:12 Desktop name 'X' (debian:1)
26/09/19 11:41:12 Protocol versions supported: 3.3, 3.7, 3.8, 3.7t, 3.8t
26/09/19 11:41:12 Listening for VNC connections on TCP port 5901
# Failed to parse arguments: Unknown option --login

As you can see in the last line there is an Error.

I fixed that by commenting the line contains "–login" in this file :)) /usr/bin/x-terminal-emulator

Then I restarted the vncserver :

parsa@debian:~$ tightvncserver -kill :1
Killing Xtightvnc process ID 910
parsa@debian:~$ tightvncserver -geometry 1024x720 :1

New 'X' desktop is debian:1

Starting applications specified in /home/parsa/.vnc/xstartup
Log file is /home/parsa/.vnc/debian:1.log

Then again lets see the log file

tail -f .vnc/debian\:1.log
# watch_established: "/org/gnome/desktop/interface/" (establishing: 1)
# watch_established: "/org/gnome/settings-daemon/peripherals/mouse/" (establishing: 1)
# watch_established: "/org/gnome/desktop/sound/" (establishing: 1)
# watch_established: "/org/gnome/desktop/privacy/" (establishing: 1)
# watch_established: "/org/gnome/desktop/wm/preferences/" (establishing: 1)
# watch_established: "/org/gnome/settings-daemon/plugins/xsettings/" (establishing: 1)
# watch_established: "/org/gnome/desktop/a11y/" (establishing: 1)
# watch_fast: "/org/gnome/terminal/legacy/" (establishing: 0, active: 0)
# unwatch_fast: "/org/gnome/terminal/legacy/" (active: 0, establishing: 1)
# watch_established: "/org/gnome/terminal/legacy/" (establishing: 0)

Now that the error is gone, I connect to vncserver , and these lines appear in the log :

26/09/19 12:18:05 Got connection from client 192.168.1.131
26/09/19 12:18:05 Using protocol version 3.8
26/09/19 12:18:05 Full-control authentication passed by 192.168.1.131
26/09/19 12:18:05 rfbProcessClientNormalMessage: ignoring unknown encoding 24
26/09/19 12:18:05 rfbProcessClientNormalMessage: ignoring unknown encoding 16
26/09/19 12:18:05 rfbProcessClientNormalMessage: ignoring unknown encoding 22
26/09/19 12:18:05 rfbProcessClientNormalMessage: ignoring unknown encoding 21
26/09/19 12:18:05 rfbProcessClientNormalMessage: ignoring unknown encoding 15
26/09/19 12:18:05 Using zlib encoding for client 192.168.1.131
26/09/19 12:18:05 rfbProcessClientNormalMessage: ignoring unknown encoding -314
26/09/19 12:18:05 Enabling full-color cursor updates for client 192.168.1.131
26/09/19 12:18:05 rfbProcessClientNormalMessage: ignoring unknown encoding -223
26/09/19 12:18:05 Pixel format for client 192.168.1.131:
26/09/19 12:18:05   8 bpp, depth 6
26/09/19 12:18:05   true colour: max r 3 g 3 b 3, shift r 4 g 2 b 0
26/09/19 12:18:05 Using raw encoding for client 192.168.1.131
26/09/19 12:18:05 rfbProcessClientNormalMessage: ignoring unknown encoding 24
26/09/19 12:18:05 rfbProcessClientNormalMessage: ignoring unknown encoding 22
26/09/19 12:18:05 rfbProcessClientNormalMessage: ignoring unknown encoding 21
26/09/19 12:18:05 rfbProcessClientNormalMessage: ignoring unknown encoding 16
26/09/19 12:18:05 rfbProcessClientNormalMessage: ignoring unknown encoding 15
26/09/19 12:18:05 rfbProcessClientNormalMessage: ignoring unknown encoding -314
26/09/19 12:18:05 Enabling full-color cursor updates for client 192.168.1.131
26/09/19 12:18:05 rfbProcessClientNormalMessage: ignoring unknown encoding -223
26/09/19 12:18:05 rfbProcessClientNormalMessage: ignoring unknown encoding 24
26/09/19 12:18:05 rfbProcessClientNormalMessage: ignoring unknown encoding 16
26/09/19 12:18:05 rfbProcessClientNormalMessage: ignoring unknown encoding 22
26/09/19 12:18:05 rfbProcessClientNormalMessage: ignoring unknown encoding 21
26/09/19 12:18:05 rfbProcessClientNormalMessage: ignoring unknown encoding 15
26/09/19 12:18:05 Using zlib encoding for client 192.168.1.131
26/09/19 12:18:05 rfbProcessClientNormalMessage: ignoring unknown encoding -314
26/09/19 12:18:05 Enabling full-color cursor updates for client 192.168.1.131
26/09/19 12:18:05 rfbProcessClientNormalMessage: ignoring unknown encoding -223
26/09/19 12:18:05 Pixel format for client 192.168.1.131:
26/09/19 12:18:05   32 bpp, depth 24, little endian
26/09/19 12:18:05   true colour: max r 255 g 255 b 255, shift r 16 g 8 b 0
26/09/19 12:18:05   no translation needed

and I see a gray screen in the vnc viewer with a black X cursor :

Could you please help me to fix this problem ?

I have googled this rfbProcessClientNormalMessage: ignoring unknown encoding error a lot but I couldn't find a solution.

here is my ~/.vnc/xstartup by the way :

#!/bin/shxrdb $HOME/.Xresources
xsetroot -solid grey
x-terminal-emulator -geometry 80x24+10+10 -ls -title "$VNCDESKTOP Desktop" &
# x-window-manager &
gnome-session &

Thank you.