Unable to get duckdns working on a fresh hass.io install

A previous install of HA in a friends house got corrupted, so I went to go and rebuild it for him…

Try as I might, on a fresh install of hass.io (v0.103.0) I first install Samba, then DuckDNS. All goes fine in the DuckDNS setup, it generates the keys etc. I update http in configuration.yaml with:

http:
  base_url: https://[mydomain].duckdns.org:8123
  ssl_certificate: /ssl/fullchain.pem
  ssl_key: /ssl/privkey.pem

and when trying to access I get the error: “[mydomain].duckdns.org unexpectedly closed the connection”.

There are no errors in home-assistant.log

We had it running previously on the same port, so I’m pretty confident its not a router issue.

Any suggestions gratefully received.

Did you open ports on your router?
Check it again, maybe your IP address changed after the install.

Try here to check if its visible from outside:
Can You See Me

It’s the same Pi running HA as before, so has a fixed IP and router forwards 8123 on…

Uninstalling the DuckDNS add-on and reinstalling it seems to do the trick - looks like the add-on needs all the config right first time and isn’t very forgiving to change it later.