jupyter notebook access issue in Chromium

I had the same issue. I don't know what the problem is with Chrome, but a quick "fix" for me was to run:

jupyter notebook --browser firefox

so I don't have to copy-paste the link in Firefox.

The issue is chromium being a snap app in Ubuntu, if the URL is used instead of the html file, the issue is resolved. jupyter notebook --generate-config will output the directory for config file, edit it and add this line c.NotebookApp.use_redirect_file = False

Your issue is probably be related to Chromium being a snap app. According to this Stack Overflow answer:

With recent versions of snap, applications installed with snap can't by default open files in hidden folders (with a name starting by .).

In Ubuntu 20.04, chromium is installed with snap (even when using the command sudo apt install chromium-browser), so chromium can't open the html file used by Jupyter.

As stated by @rahul-sood, a simple workaround is to copy-paste one of the alternative links given by Jupyter in the terminal (starting by http://localhost:8889/?token= or http://127.0.0.1:8889/?token=).

This snap issue is also mentioned in this Ask Ubuntu answer:

The Snap 'home' interface permits access only to non-hidden files and directories in a user's /home.

The Snap 'personal-files' interface permits access to all files and directories in a user's /home.

• Snap interfaces are defined in the yaml file used in snap creation.
• The personal-files interface requires an additional $snap connect foo:foo-connect. The home interface does not, which makes it more convenient for some uses.

Also see this relevant thread in the snapcraft forum: Can browsers open local files?

Summarizing, this is probably an issue due to Chromium being a snap application. Your options are:

• Copy and paste one of the links starting with http://localhost:8889/?token= or http://127.0.0.1:8889/?token= in Chromium to open your notebook in it.

• Use another non-snap browser as default.

• Use the command mentioned by Salvatore Lampitelli to open the notebook in the specified non-snap browser.

Generate a jupyter config file in terminal using commands:

jupyter notebook --generate-config

open the script jupyter_notebook_config.py in the directory
/.jupyter and uncomment the line 531 : Set c.NotebookApp.use_redirect_file = True to
c.NotebookApp.use_redirect_file = False. It will work.