Comment 3 for bug 1779163

Hmmm, I think the issue we'll find here is that the model has a fan network setup but the controller itself isn't participating in it. You might need to see the controller with the same fan config as the model when you bootstrap and set model config so that there's a known route from the controller you're ssh'ing through (with the --proxy) to the lxd container that you're trying to reach in another model. By default there's not a known route from the controller to each lxd instance.

Juju is working because the lxd units reach out to the controller which has a reachable address. Things going the other way around will have issues. Setting common fan config would give that path.