It is deployed on an on premise, secured network that has no access to the outside world.

Is it password protected or something of that nature?

Perhaps we could find a different solution or work around, rather than solving a technical issue.

Solving it means allowing the python code to ask the JupyterLab server for the notebook file

However, once working with ClearML and using a venv (and not the default python kernel),

Are you saying on your specific setup (i.e. OpenShift+helm etc) in some occurrences everything work and on some it does not?