[lubuntu] 16.04 Server X11 unable to open display ":0"

hi, i installed 16.04 server.
sudo apt-get install xorg
sudo apt-get install wmctrl
sudo apt-get install chromium-browser
sudo apt-get install libexif-dev

export DISPLAY=:0
starting xhost +
or chromium-browser terminates with error

unable to open display ":0"

in 14.04. there was the /etc/X11/Xwarapper.config
This is not available in 16.04