Problem to load css and Js offline

I’m trying to run a dash app on a local network without internet access. Offline.

I also add the commands:
app.css.config.serve_locally = True
app.scripts.config.serve_locally = True

The browser tries to load the css and js files from the unpkg online CDN and does not load them from the local files.
Which makes the screen blank with the word “Loading …”

I spent hours on it, I would be very happy to help