Error: an attempt was made to access a socket in a way forbidden by its access permissions

Is the prodigy.json available in the right place in your Docker container? It looks like it's not being read correctly, since the server starts up on the default localhost with port 8080.

In a containerised environment, it might be better to use the environment variables PRODIGY_HOST and PRODIGY_PORT. Alternatively, here's a starter dockerfile that uses a template for the prodigy.json: Cloud deploy dockerfile