Unable to access grafana behind reverse proxy

Grafana
1

I’m running a grafana server using the official docker image (v7.0.0).
The proxy server forwards requests to {proxy.ip}/prod/grafana to {grafana_server.ip}:3000(which grafana container listens to).
I’ve edited grafana.ini as follows and restarted container.

root_url = http://{proxy.ip}/prod/grafana
serve_from_sub_path = true

(where {proxy.ip} is actually just a string like 1.2.3.4)

When I access the URL http://{proxy.ip}/prod/grafana, I get If you're seeing this Grafana has failed to load its application files error.
And devtool console shows the following.

bootstrap:84 Uncaught TypeError: Cannot read property 'call' of undefined
    at i (bootstrap:84)
    at a (axes_editor.html:2)
    at annotations.editor.html:2
    at Array.forEach (<anonymous>)
    at Object.Sr1g (annotations.editor.html:2)
    at i (bootstrap:84)
    at Object.HJRA (jsontree.ts:20)
    at i (bootstrap:84)
    at Object.AVRW (app.41bc4b193210d0f899b3.js:2)
    at i (bootstrap:84)

Looking at network tab, all requests to server is returning 200. So there seems to be no asset files unfetched.

I cannot provide config on proxy server as it is run by another team.
Can anyone guess why this isn’t working?