Remote access Arris NVG468MQ


I had HA running on a Raspi docker image for a while and was able to setup remote access with my DLink router and a dyn dns service without any problem.
But I cannot get it to work with my new Arris NVG468MQ. I have port forwarding configured and I’m able to log in, but after that the UI is hanging for a while trying to load data and then it shows unable to load data.
I tried a lot of things, adding a proxy (caddy and haproxy), nothing worked.
If I used the Lan IP address from a local computer, everything works fine.

Has anybody been able to get it to run on the router?
I’m using Home Assistant 0.101.3 running in docker.