Duckdns connecting from inside but not from outside

Hi! Apologies in advance if this post is misplaced :frowning:
I recently set up the Duckdns feature. Great and amazing.
Nevertheless, what happens seems curious, to me. I can access from inside my LAN, but not from outside. A few important notes:

  • It is working (from inside the LAN) with the https:// prefix, everything working and encrypted.
  • I have set the ports to redirect the external 443 to the internal 8123.
  • My network configuration consists of a ISP router in bridge mode and a TP-Link Deco as acting router (in router mode).
  • The IP that appears at my duckdns.org dashboard is the same as my TP-Link Deco provides. It does not look like a CGNAT dynaimc IP issue.

Does anybody know why I cannot access my Home Assistant setup from outside the network? Thank you very much in advance!