`404 : Not Found` when trying to open a png file

[ivsanro1]

Description

When I try to open a png file using the jupyter file explorer (while using nbclassic), it says:

404 : Not Found

You are requesting a page that does not exist!

But as soon as I remove nbclassic from the url, it works properly, showing the image.

Reproduce

1. Launch jupyter with nbclassic: jupyter nbclassic
2. Create a png picture and put it where you can access with the explorer from jupyter
3. Be sure that you're using the explorer with nbclassic (url has to be like this: http://localhost:3025/nbclassic/view/repo/image.png
4. Try to open it with jupyter explorer (nbclassic)
5. Once it says 404 not found, remove nbclassic form url to use original jupyter explorer, and it shows the image properly

Expected behavior

Image shows fine, not indicating a 404 error. Just like it works using original jupyter explorer

Context

Operating system (server):

Distributor ID: Ubuntu
Description:    Ubuntu 22.04.3 LTS
Release:    22.04
Codename:   jammy

Libraries:

jupyter==1.0.0
nbclassic==1.0.0

Python

Python 3.10.12 (main, Nov 20 2023, 15:14:05) [GCC 11.4.0] on linux

[RRosio]

I wanted to note here that I can replicate this behavior after launching NbClassic when Notebook 7 has been installed.