Jupyter Notebook: Terminals not available

Yesterday I had problems launching Jupyter Notebook (all of sudden I got the notification, that python was not working properly, but before everything was working well...). So I decided to upgrade to the latest python version. And now I can launch jupyter notebook, however I get this error message:

Terminals not available (error was No module named 'winpty.cywinpty')

I followed the setps descriebd here:

But still get this error message. Is there a way, to solve this? Or does anyone have an advise?

EDIT: This is what I get when I run jupyter notebook from the cmd:

[W 14:17:04.451 NotebookApp] Terminals not available (error was No module named 'winpty.cywinpty')
[I 14:17:05.073 NotebookApp] JupyterLab extension loaded from C:\Users\Fati\AppData\Local\Programs\Python\Python39\lib\site-packages\jupyterlab
[I 14:17:05.073 NotebookApp] JupyterLab application directory is C:\Users\Fati\AppData\Local\Programs\Python\Python39\share\jupyter\lab
[I 14:17:05.323 NotebookApp] Serving notebooks from local directory: C:\Users\Fati
[I 14:17:05.324 NotebookApp] Jupyter Notebook 6.1.5 is running at:
[I 14:17:05.326 NotebookApp] http://localhost:8888/?token=8e859b3108946a8310e1e5ceed6d2186c8731261fc5161eb
[I 14:17:05.330 NotebookApp]  or
[I 14:17:05.331 NotebookApp] Use Control-C to stop this server and shut down all kernels (twice to skip confirmation).
[C 14:17:05.448 NotebookApp]