Proxmox does say docker isn’t supported in LXC but I’m running 10 docker containers with no issues on an LXC. That being said I have recently had some weird database not connecting issues and other strange new docker containers not working in an LXC for some reason. If you can I would try the same setup but in a VM and see what happens.

I recently was trying to get authentic setup via docker and it just wouldn’t work. I gave up and spun up a VM, ran the same docker compose file and it worked right away.

Hopefully this helps?