...
Page-attached notebooks do not render within the Insert/Edit macro browser preview window or in-page. Instead, an “Atlassian authorization” error is displayed.
...
There There are two three known causes of this erroneous behavior:
Missing space permissions for the app
App is not allowed to view a restricted page and its attachments
IP allowlisting is enabled
Notebook URL is from an unsupported location
Solutions
Space permission
...
Disable this Confluence Cloud feature for the site
Whitelist the IP range used by Jupyter Viewer
The app uses the Heroku platform in the European zone, so the IP used may be from anywhere in the AWS European range. The latest AWS IP ranges can be programmatically queried by following the AWS guide.
Supported notebook locations
Check that the Notebook URL is from a supported notebook location.
Page Restrictions
If the Confluence page has restrictions, allow the app "IPython Notebook Viewer for Confluence" to view the page.
...
Is it possible to define an external Jupyter renderer for IPython Notebook Viewer for Confluence?
...