As it says in the subject, http://hassbian.local:8123 and http://hassio.local:8123 won’t load my Home assistant but https://xxx.duckdns.org/8123 and http://192.168.1.x:8123 work fine.
Is there a reason for this?
I’m half okay with it expect that my wife’s and daughter’s iOS phone won’t let me load the external link so it’s stuck not giving me the phones data.
I’d suggest to first look at the settings in your router. It depends on the possibility (or permission) to resolve local domain names.
What router do you have and do you have something like PiHole or Wireguard?
On the other hand, you should look, why iOS isn’t accepting the duckdns domain. Normally the router should be the one, who is looking for the sc DNS rebind, not the iPhone.