I would like some help with external connection problems

Configuration
1

Hi everyone. This is my first post in this forum. I have come to a problem the last week. I cannot connect to my my homeassistant instance externaly (duckdns). I can connect to it while being in the same network while typing the ip and the port.
But when i try to connect through ddns, it loads the loading screen, but after a while it comes with the loading screen message (failed to connect/retry now).

I have:

  • restarted ddns and reinstalled it (after nothing happened with the restart)
  • i rechecked everything in my router configuration (port forwarding)
  • restarded home assistant and rpi5

The problem began with core update 2026.2.* and continued with the 2026.3 update.
Do you have any ideas about this problem? Thank you in advance.

Screenshot 2026-03-07 192647
Screenshot 2026-03-07 1926471699×781 14 KB

2

Go to the duckDNS admin website (where you set up your domain) and check that the IP reported there matches the public IP of your router.

Also check the DuckDNS addon/app logs.

3

Hi Tom and sorry for the late reply,
thank you so much for your answer. I checked that. everything matches regarding the IPs.
Also, no errors regarding duckdns logs.
Do you think that there might be any problem with my ISP? (maybe changed my dynamic IP to NAT ip). I haven’t kept track of my IP changes.
Thank you.

4

If it was CGNAT the IP addresses would not match.

1 Like
5

Tom you were right. I didn’t realize that my router’s IP was private. Checked this again this morning. CGNAT was in front of me… Thanks a lot!

6

Ask your ISP to turn it off. Some do it for free.

1 Like
7

Good morning Tom. I did ask them, but they didn’t. So i ended up purchasing a static IP address, since i’m planning to also create some other services. It was actually the first time seeing an ISP giving NAT IPs to clients. I thought that CGNAT was only used in mobile data…