Test Heroku Deployment of Example Lumen dashboard

I have followed the panel docs and arrived at the following attempt to deploy a test app to Heroku using one of the existing lumen examples that works locally: GitHub - EliPinkus/lumen-test: attempting to deploy a lumen app to Heroku

The app crashes after loading the UI but before loading the data.

This is the log that gives way to the crash:
2022-02-22T02:20:40.879521+00:00 heroku[router]: at=info method=GET path="/test/ws" host=lumen-heroku-test.herokuapp.com request_id=56c0e0ff-af72-41d5-a58e-b83144effe93 fwd=“” dyno=web.1 connect=0ms service=381ms status=101 bytes=224 protocol=https