Randomly closing ports

Hey there,
this is my first post her because I was not able to find any helpful answer on the internet.
I am running some VMs on a proxmox server. One of which is a unprivileged LXC with keyctl and nesting enabled. This Container is running Docker with all my Containers. On another VM I am running nginx as a reverse proxy.
Now my problem is that it seems like the Docker LXC randomly closes all ports. If this happens I am getting a 502 error on all redirected Domains. After running nmap DOCKER_IP on the Reverse Proxy VM all ports seem to be open again and the redirections work like I would expect them to. After a view minutes the whole process starts again and all ports seem to be closed.

I do not know what error logs to attach. But I kindly provide all if it might help.

Hope someone can help me figuring this out.

With best regards
Lukas