Extension hangs when accessing via code server behind a load balancer

[gs-scooter]

We have a data science platform on AWS where we spin up developer EC2 instances that host ECS containers. Here's the setup:

• The container exposes two ports: one for JupyterHub and the other for VSCode server for web-based IDE purposes.
• The ECS service is configured to deploy the containers on EC2 instances via an auto-scaling group.
• The EC2 instances are in a private subnet behind a load balancer. Path pattern matching is used on the listener to direct traffic to the correct target group / port.

With this configuration, I am able to successfully browse to Jupyter Lab's web app and the VSCode server. The issue occurs when trying to create a new notebook. It seems as though the extension just hangs and never completes the notebook initialization (i.e., the progress bar keeps going at the top of the window). There are no errors in any of the output windows, so I don't know where things are going wrong. For what it's worth, the extension works fine when reproducing this on a local container on my desktop, so I'm inclined to think that something with the LB setup is causing pain.

Should the extension theoretically work in the above scenario? Any thoughts would be greatly appreciated.