DOCKERCLOUD_CONTAINER_FQDN does not resolve externally

According to the documentation here the DOCKERCLOUD_CONTAINER_FQDN environment variable contains a fully qualified domain name that should be externally available - however this does not seem to be the case with any of my deployed containers. Is there a configuration of some sort that I may have overlooked?

Can you share the output of “dig $DOCKERCLOUD_CONTAINER_FQDN +trace”?