I’ve been using Home Assistant from my Raspberry Pi 4 since May with no problems with my internal or external url through duckdns. Recently I decided to switch to boot from usb and this changed my internal url. I went supervisor and change it back and everything worked. Now (a couple days later), the external url through duckdns is not working. I still have access through the internal url but I don’t see any errors in the logs concerning duckdns or my external url. Does anyone know how I can remedy this?
What I would recommend is to verify what duckdns is resolving and compare it to your actual IP address. To do that do two steps: First go to Google and search “what is my ip address”. This should return to you your true current external ip address. Second, from any computer and ping your external duckdns URL (no ports needed) and see if the IP address you are getting back is the same as your actual IP address that google showed you.
If two numbers do not match - If that is the case manually log into duckdns and update the IP address for your home assistant url and then try to access it externally again. If this fixes the issue you duckdns integration in Home Assistant is not updating your IP address correctly and you may want to confirm that config.
If the two numbers do match - you may want to verify the port forwarding setup in your router.
That was it. Yesterday my wifi was acting weird and wanted me to reset my admin password. I guess it deleted my port forwarding along with that.