lookup registry-1.docker.io: no such host

I have docker daemon running on my Ubuntu 16.4 server

my server details:

No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 17.04 Release: 17.04 Codename: zesty

I'm receiving the following error:

aa@aaa-VirtualBox:/etc/default$ docker run hello-worldUnable to find image 'hello-world:latest' locallydocker: Error response from daemon: Get https://registry-1.docker.io/v2/: dial tcp: lookup registry-1.docker.io: no such host.See 'docker run --help'.

I have set the http_proxy and the https_proxy beacuse i'm behind a corp proxy/firewall

Any clues how I can fix this issue?