https://github.com/microsoftgraph/microsoft-graph-docs/issues/2624
I am experience the issue as the above.
I am trying to save the content of a page with a reference to an image by calling https://graph.microsoft.com/v1.0/users/{userId}/onenote/pages/{pageId}/content?preAuthenticated=true
Per this - Downloading one note page with image content as HTML
By appending "?preAuthenticated=true" when you do the fetch, it will make the image public.
But when I tried to render the html, it's giving me "Failed to load resource: the server responded with a status of 401 (Unauthorized)".
Bit of off topic, but I figured out how to get the image to render.
https://learn.microsoft.com/en-us/graph/api/resource-get?view=graph-rest-1.0&tabs=http
When you call /onenote/pages/{id}/content, the image has a reference to a source like this
src="https://graph.microsoft.com/v1.0/users({userId})/onenote/resources/{resourceId}/$value" along with data-src-type="image/jpeg"
do a get request to this endpoint and you'll the image binary, convert the binary to base64, and then just render the html by replacing the src with base64.