nbconvert not working in VSCode and jupyter notebook

Question

I want to convert one of my .ipynb (jupyter notebook) files to markdown(.md) for my github.

1. I try the code jupyter nbconvert --to markdown 'name_of_project.ipynb'
2. And use vscode extension jupyter to markdown
3. In jupyter notebook, File > Save and Export notebook AS > MarkDown

But in all of ways, i face the this error.

• Python and Jupyter exist in my Environment-Path

and when type command in virtual-env, face this :

[NbConvertApp] WARNING | pattern "'Blood_Cell_Cancer.ipynb'" matched no files
This application is used to convert notebook files (*.ipynb)

Error Image

1. I try the code jupyter nbconvert --to markdown 'name_of_project.ipynb'
2. And use vscode extension jupyter to markdown
3. In jupyter notebook, File > Save and Export notebook AS > MarkDown

• Python and Jupyter exist in my Environment-Path