Problème using Voilà on my slicer JupiterKernel

Good afternoon,

What is Voilà? Voilà turns Jupyter notebooks into standalone web applications.

I tried opening my SliceletVideoEtienne .ipynb file that has code that run a Slicer app in the jupyterNotebook, using voilà but got this error : 404 not found ?
I tried the exact same thing, opening a file .ipynb with simple python code print(“salut”) using voilà and it worked, only the result is being shown, the code is hide:

Have any of you encountered the same issue? Or, knows a better way?

Big thanks in advance,