I don’t have Unifi gear but, after correctly forwarding port 80, expectations are to be able to access Nginx greetings page (with the default NPM settings), not Home Assistant.
Basically, after forwarding ports 80 and 443 to the IP of the machine running NPM it should point as following:
- http://192.168.0.1 or http://192.168.0.1:80 (internal ip of the router) => router’s configuration webpage;
- https://192.168.0.1:8443 more likely than https://192.168.0.1:443 (internal ip of the router) => router’s configuration webpage (if enabled in the router’s settings; usually only http access is configured);
- http://192.168.1.1 or http://192.168.1.1:80 (external ip of the router) => Nginx greetings page;
- https://192.168.1.1 or https://192.168.1.1:443 (external ip of the router) => should go to http://192.168.0.x:8123 and should result in an error as the certificate was issued to https://youraddress.duckdns.org (DuckDNS record of http://192.168.0.x:8123)
- http://192.168.0.x:8123 => Home Assistant
