node.js website deployed to Azure - 404 failed to load a .json resource

I have a node.js Web App in Azure,

the site loads the index.html, the css, images, etc. but the JS search functionality doesn't initialize, I did an F12 inspection in Chrome and saw this error

[domain]http://.azurewebsites.net/data/policies.json Failed to load resource: the server responded with a status of 404 (Not Found)

in the Azure console I can see the file list

> cd public
D:\home\site\wwwroot\public

> cd data
D:\home\site\wwwroot\public\data

> ls
D:\home\site\wwwroot\public\data

policies.json

according to the folder/file structure (everything is in the /public folder) I have made a configuration change as follows

/ = "site/webroot/public"

the folders are laid out like this

/public/index.html
/public/data
/public/js
/public/css

etc

Without the config setting the website doesn't see /public as the root folder, so it doesn't find the index.html and nothing loads.

So the site loads, which is great, the images and css load, which is great

but it says it can't find the .json file in the data folder? (and using the console the file is definitely there!)

please advise.