Python VS code does not connect with IPython kernel

An issue was opened today in the Python VS Code repository that describes a similar problem. Their recommended fix is to close VS Code and then revert the traitlets dependency to version 4.3.3 with this command:

python -m pip install 'traitlets==4.3.3' --force-reinstall

the reason is newer version of traitlets (5.0.0) installed by VSCode into the new virtual environment;
but the ipykernel and tornado is incompatible with ipykernel and tornado;
run the code in Terminal:
pip install –upgrade ipykernel
pip install –upgrade tornado

Updated 2023.01.18 – Started 2023.01.15

Problem description: Jupyter in VS Code got stuck at connecting to Python kernel

I was using VS Code version 1.74.3 (user setup) with the Release Python extension version v2022.20.2, having the version details shown below:

My Python version was 3.10.6 64-bit:

I tried all methods mentioned in all of the above answers, and none worked for me to get Jupyter unstuck.

I ran the Python 3.10.6 setup to repair it, but that did not work:

I updated various packages, but that did not work either:

• pip install –upgrade ipykernel
• pip install –upgrade traitlets
• pip install –upgrade tornado

Some details from the above upgrades:

• Requirement already satisfied: traitlets>=5.4.0
• Requirement already satisfied: tornado>=6.1
• (from ipython>=7.23.1->ipykernel)

Method 1: After uninstalling and reinstalling VS Code, Jupyter worked as before.

When I installed the Pre-Release Python extension (by mistake),

Jupyter got stuck again. I uninstalled the Pre-Release Python extension, and re-installed the Release Python extension shown in the image above; Jupyter worked again.

The problem with Method 1 is that once VS Code was ended and reopened, the same problem occurred again. Use Method 2 below.

Method 2: Run jupyter-notebook, connect to Jupyter server

In addition to the Jupyter-related extensions that came with installing the Python extension,

install jupyter:

> pip install jupyter
... cut ...
Successfully installed jupyter-1.0.0

Run jupiter-notebook in a VS Code terminal:

> jupyter-notebook
[I 11:47:56.970 NotebookApp] Serving notebooks from local directory: C:UsersUSERDocumentsVS Code - learn
[I 11:47:56.971 NotebookApp] Jupyter Notebook 6.5.2 is running at:
[I 11:47:56.971 NotebookApp] http://localhost:8888/?token=3e14829cf931c6aa61474c740ddf09eb34bd457f3dba20b3
[I 11:47:56.971 NotebookApp]  or http://127.0.0.1:8888/?token=3e14829cf931c6aa61474c740ddf09eb34bd457f3dba20b3
[I 11:47:56.971 NotebookApp] Use Control-C to stop this server and shut down all kernels (twice to skip confirmation).
[C 11:47:57.000 NotebookApp] 

To access the notebook, open this file in a browser:
    file:///C:/Users/USER/AppData/Roaming/jupyter/runtime/nbserver-13876-open.html
Or copy and paste one of these URLs:
    http://localhost:8888/?token=3e14829cf931c6aa61474c740ddf09eb34bd457f3dba20b3
 or http://127.0.0.1:8888/?token=3e14829cf931c6aa61474c740ddf09eb34bd457f3dba20b3
[W 11:48:36.001 NotebookApp] Forbidden
[W 11:48:36.001 NotebookApp] 403 GET /api/sessions?1673977715999 (127.0.0.1) 1.000000ms referer=None
[W 11:48:37.425 NotebookApp] Forbidden
[W 11:48:37.426 NotebookApp] 403 GET /api/kernels?1673977717423 (127.0.0.1) 1.000000ms referer=None
... cut ...

Jupyter notebook opened up in my browser; I closed this Jupyter notebook tab since I did not need it:

Open Command Palette (Shift+Ctrl+P) or

Select Jupyter: Specify Jupyter Server for Connections, and select Existing:

Put in the box the URI (Uniform Resource Identifier) of the existing server obtained from running jupyter-notebook above, i.e.,

Press Enter.

Close the current Jupyter interactive window and Run Cell 1 of my Python code again:

Problem solved.

The next day, just repeat Method 2 after running VS Code again.

Method 3: Downgrade Jupyter extension

Based on the suggestion in the answer Python VS code does not connect with IPython kernel just below my own answer here, I downgraded the Jupyter extension from v2022.11.1003412109 to v2022.9.1303220346, but it did not work. Below are the details (since I could no longer edit my comment to that answer).

Open up the list of extensions:

Click on the Settings button for Jupyter, and select Install Another Version:

Reload this older Jupyter extension, and do NOT update:

Click on Run Cell 1, but Jupyter window did not open up:

Nothing happened. I uninstalled jupyter package, same problem.

So I stick to Method 2 above with the latest Jupyter extension (not downgraded), and everything was working again.

I had the same problem and none of the solutions above worked for me.
I succeded to resolve the problem by dowgrading Jupyter version from v2022.11.1003412109 to v2022.9.1303220346 in the extension manager.