I have setup Duckdns and Lets encrypt and port forwarded only 443 to 8123 and it works the only thing i’m not sure I should worry about or not is that when I try to access my HA running on pi3 from WAN (using a proxy) the page never loads if i use https://SubDomainName.duckdns.org BUT if I add a port number at the end :8123 it loads and the browser shows secure connection. I have made sure that the port forward is setup but still it’s not working without adding a port number in the address am i missing something here or something wrong with my router ??
Ok So I was able to access it with the DuckDns address using the Proxy Extension in the browser but it was still on LAN,I looked at the connections and addresses using the Netstat command on the Pi. Then I turned off Lan Loopback and I lost access using the DuckDns address I also tried to access it using a 3G connection on the Phone but no success. Then I opened the Router Settings page and made the Port forwarding Rules again 443 > 8123 BUT i changed the PPPoE Interface and used the Second one out of the Two available and Now IT’S WORKING and I can access it from WAN (3G) just by using the https://example.duckdns.org only and no port number after it