Connection refused error while deploying RHOSP14 undercloud

Issue

• While Creating container-images for undercloud, it throws an error connection refused

  [stack@manager ~]$ sudo openstack tripleo container image prepare   -e ~/containers-prepare-parameter.yaml
  Error inspecting image: docker://registry.access.redhat.com/rhosp14/openstack-aodh-api:latest
  time="2019-02-26T16:38:54+08:00" level=fatal msg="pinging docker registry returned: Get https://registry.access.redhat.com/v2/: dial tcp: lookup registry.access.redhat.com on [::1]:53: read udp [::1]:46192->[::1]:53: read: connection refused"