Unable to connect to home assistant via external domain

Hello,

  • I am unable to access my HA remotely. The connection times out (not refused, but timing out).
  • I am running Home Assistant OS with Supervisor on a Ubuntu VM.
  • I have port forwarding set up for external connections to another port (not default 8123).
  • I am using DuckDNS with built in Let’s Encrypt, so no HTTP access, only HTTPS
  • The SSL certificate is fine and valid.
  • I can connect internally via my IP on port 8123, but I cannot connect externally.
  • Port forwarding is working to the VM. To confirm this, I set up the SSH add-on and was able to access ssh externally just fine! It’s just main HA access not working.
  • A while ago I had the same issue, and updating Home Assistant to the latest version made everything work fine for a while. I am running the latest HA version and OS.
  • I cannot see any issues in any logs.
  • I’d rather not complicate the scenario with a reverse proxy as everything worked for a long time. Nothing has changed AFAIK.
  • I don’t have IP banning enabled or anything like that in my HTTP section of the config.

Help is appreciated.

EDIT:
I edited the config to remove the HTTPS settings.
No difference externally on HTTP vs HTTPS - still cannot access HA, so I switched it back to HTTPS

OK, so I’m still unsure if the issue was some software routing issue with HA, or my router, but I changed the external port to match that of the internal port, and that works.
Never been an issue before, but I’m working again now.