IP address works but not localhost or homeassistant.local

I can access the homeassistant UI by going direct to my IP (192.168.), but not via homeassistant.local or localhost. I’m running HA on a Synology NAS inside a docker container using network=host. It’s not a huge deal, but I’m trying to learn from all this and so I’m just curious what might be going on? Any ideas?

First, localhost is a machine/VM-only access, so that should not be possible to be used.

If you can access it through IP, then it is only your mDNS that seems to be affected.
Make sure that the .local domain is not registered at your DNS server, because it is a serverless protocol.
If you have changed the name of your HA server in the network settings, then this will be the mDNS name with .local suffixed.

Thanks for your help! I’m trying to access via a Mac Studio, not directly on the Synology so the localhost thing makes total sense to me now. But I think the issue is with HA as when I go to Settings->System->Network it’s just a blank screen? It also seems like the server name isn’t even being set? Am I missing an ENV variable in my docker YAML?

You might be running a core installation, instead of HAOS.
With a core installation the mDNS name might be set in the hostOS instead, so try to use the synology mDNS name suffixed with .local, instead of homeassistant.local

Yup you were correct. I am running HA Core inside of docker. I guess only the HAOS includes the network name. I was able to use the .local along with the DNS name of my NAS and that worked. Thanks for your help!