What is causing the kernel when you start up a env

I have several virtual environments in y Jupyter Notebook. I just added a new one and the kernel for it
fails to start,

It says kernel starting and then it fails with a message like “connection fails”.

I try again and it still fails.

What is causing this and how do I fix it?

Any help appreciated. Thanks in advance.


This is probably due to the kernelspec referencing a partially installed env. I would recommend running: jupyter kernelspec list, identifying the location relative to the kernel you’re currently having issues with, and checking that location’s kernel.json file’s argv entry to ensure it’s running a valid executable.

If you still have issues, please post the notebook console’s contents relative to the startup of the kernel (which should include relative traceback information, etc.) and we’ll see if anyone has further ideas.

You might also find additional information is logged by adding --debug to your notebook server’s start command.