Docker behind the corporate proxy - proxyconnect server misbehavng

Hello,
I’m getting:

Error response from daemon: Get https://registry-1.docker.io/v2/: proxyconnect tcp: dial tcp: lookup http on xx.xx.xx.xx:53: server misbehaving

when trying to pull or run a docker image. Suspect that something is wrong with the proxy configuration.

I’ve set the docker service environment as follows:

Environment=HTTP_PROXY=http://domain\domain_user:password@proxy.abc:port HTTPS_PROXY=http://domain\domain_user:password@proxy.abc:port.

The thing is that I’m behind a corporate proxy that requires domain user/password basic authentication.

Could you confirm that the above synax is correct and that the location /etc/systemd/system/docker.service.d/docker.conf is the right place to set the environment.

I’m running Docker version 19.03.2, build 6a30dfc

Regards,
Nenad