Jupyter Lab iframe fails when not running on localhost

Must be something to do with Traefik. Have tried a bunch of different options for allowing origins when running the local Jupyter server. All of the websocket requests were failing.

Start by reproducing the Jupyter Lab iframe failure when it is not served from localhost, then inspect the Traefik configuration and the local Jupyter server's allowed-origin settings. Trace the failing websocket requests and confirm that the iframe works outside localhost with all websocket connections succeeding.

Written by the indexing model from the issue text.