I have successfully setup duckdns with certificate and can login fine, however since setting up I cannot access it on a local IP, only via the external duckdns link
Is this meant to happen or should I also be able to access locally (i.e. hassio.local or the IP?)
Your browser will likely throw a warning but you can click through it.
You should be able to specify your duckdns address internally and have it work. It may require some settings updates on your router for NAT reflection/loopback.
do a CTRL+F for the heading ROUTING TRAFFIC LOCALLY
but itβs pretty easy to just set a static IP address to the pi/device/VM and then do https://192.168.1.x:8123
(replace x with your local ip) when you want to access locally instead of via your duckdns address