#####Note that it isn't compatible with Firefox snap version. The firefox-esr must be installed.#####
sudo /usr/sbin/ip netns exec instance1 env http_proxy="" https_proxy="" \
sudo -u $USER \
env DISPLAY=$DISPLAY XAUTHORITY=$XAUTHORITY firefox-esr --new-instance --profile $HOME/.mozilla/instance1

sudo /usr/sbin/ip netns exec instance2 env http_proxy="" https_proxy="" \
sudo -u $USER \
env DISPLAY=$DISPLAY XAUTHORITY=$XAUTHORITY firefox-esr --new-instance --profile $HOME/.mozilla/instance2

sudo /usr/sbin/ip netns exec instance3 env http_proxy="" https_proxy="" \
sudo -u $USER \
env DISPLAY=$DISPLAY XAUTHORITY=$XAUTHORITY firefox-esr --new-instance --profile $HOME/.mozilla/instance3