Sudores on lxd container

i have a ubuntu lxd container (on ubuntu 18.04).
i add a domain group in visudo. and run lxc set security.priviliged true on my lxd docker.
i try to update ubuntu 16 as domain user in sudores group:
return error : sudo apt update
sudo: unable to resolve host “my-host”
sudo: no tty present and no askpass program specified.