SSLError SSL_ERROR_RX_RECORD_TOO_LONG

Hi,
I’m new to urbackup and wanted to give it a try.
I installed the Docker Hub on a debian 11 container on proxmox.
I did the same last week and was able to access the urbackup GUI. However, when I tried to access the docker image on https://192.168.1.16:55414/, I got the message SSL_ERROR_RX_RECORD_TOO_LONG in Firefox.
As I assumed I did some misconfig, I deleted the old container and started from scratch.
Unfortunately with the same result. I couldn’t find helpful posts on this message in combination with urbackup. Is this releated to debian or to urbackup?

As I am using Debian as OS anyway, I am wondering if a VM or a container on proxmox would work best? Are there any recommendations? The docker has the advantage, that I can directly mount the path /ZFS/clientbackups without monitoring the diskspace used within the VHD of a VM.

Cheers, Markus

I started from scratch with a container based on Debian 10 and followd the instruction for Suse/Debian.
Now it is working fine.