How to configure grafana behind reverse proxy ingress nginx controller

Hi,
Installed kube-prometheus operator with Helm and modified values.yaml with recommended changes for Ingress URL. I have tried different options but still getting following message when I go to mysb.grafanasite.com. Any clues what else needs to be fixed?

**If you're seeing this Grafana has failed to load its application files**

1. This could be caused by your reverse proxy settings.

2. If you host grafana under subpath make sure your grafana.ini root_url setting 
 includes subpath. If not using a reverse proxy make sure to set 
 serve_from_sub_path to true.

3. If you have a local dev build make sure you build frontend using: yarn start, yarn 
start:hot, or yarn build

4. Sometimes restarting grafana-server can help

I see below settings in grafana.ini file inside Grafana pod.

[analytics]
check_for_updates = true
[grafana_net]
url = https://grafana.net
[log]
mode = console
[paths]
data = /var/lib/grafana/data
logs = /var/log/grafana
plugins = /var/lib/grafana/plugins
provisioning = /etc/grafana/provisioning
[server]
root_url = https://mysb.grafanasite.com/