I use duckdns to access home assistant remotely using the web browser, or the home assistant app on my iPhone. But if my internet goes down, I dont have any way to access home assistant that I know of while at home. If I go to the internal address http://192.168.1.141:8123, that does not work. Can someone tell me how I can access my home assistant if my internet is down, or duckdns is having issues? I just cannot seem to find a way. This is the entry I have in my configuration, it works great when my internet is working.
I didn’t understand your problem at first, I thought you were tying to access hass form outside when you internet goes down.
That private ip address should work, check if its right, or if you have multiple wifi repeaters, connect to the same one or (preferably) connect your server directly to your ISP’s modem.
There’s no reason I can think of, for your hass being accessible from wan (internet) but not from lan (your home). Maybe check there are no firewalls activated on your router.