I have a remote access problem from the Android app on my tablet.
I have configured access via DuckDns and everything works fine, I can connect on remote access via browser (from pc, tablet or smartphone) and via android app (from smartphone, the tablet don’t have SIM for mobile data)
When I’m on a local network, the Android app (if I set internal url as https: //homeassistant.local: xxxx) gives me a certificate error (on smartphone and tablet), like browser, but on the contrary of the browser don’t ask me to continue.
Therefore I use the external url even when I am on a local network.
The problem is that this thing works on the smartphone, but not on the tablet, despite being configured the same way.
There are many topic addressing this issue.
Since you use https, https: //homeassistant.local:8123 will be an invalid certificate, as it belongs to duckdns.org
Your need to use the same address both external and internal (with or without :8123, but that depends on which solution your using)
So in order to fix it, you need hairpin NAT, reverse proxy (NGIX) or run your own DNS server…
I tried to configure NGINX, but the situation remained the same, from the network I continued to access with smartphone and pc but not with the tablet.
I uninstalled and reinstalled the app on the tablet and now it works, with or without NGIX…