Great, let’s start again.
So you have two LXC containers and within each you installed standard Docker CE (not Swarm) and run multiple services/containers incl. Traefik.
How do you enable inter LXC communication? Did you set up some kind of routing? Or some kind of port forwarding?
By default containers are all about isolation, so by default one Docker in LXC should not be able to talk to another Docker container in another LXC.