Alt keys not working

Technical Help
1

Tensorbook;

Suddenly alt Left and Right keys stop working.

uname -a

Linux tensorbook 5.3.0-61-generic #55~18.04.1-Ubuntu SMP Mon Jun 22 16:40:20 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux

lsb_release -a

Distributor ID: Ubuntu
Description: Ubuntu 18.04.4 LTS
Release: 18.04
Codename: bionic

cat /etc/default/keyboard

XKBLAYOUT=“us”
XKBVARIANT=“”
BACKSPACE=“guess”
XKBMODEL=“pc104”
XKBOPTIONS=“terminate:ctrl_alt_bksp”

echo $XDG_SESSION_DESKTOP

gnome

echo $XDG_SESSION_TYPE
x11

dconf read /org/gnome/desktop/input-sources/xkb-options

[‘terminate:ctrl_alt_bksp’, ‘caps:ctrl_modifier’, ‘ctrl:nocaps’]

xmodmap -pke

xmodmap2020

Please let me know if you need any info.

I appreciate your help.

Thanks.