Grafana Proxy New Domain to old DOmain - nginx

Question

I am currently running a Grafana server with an NGINX server in front of it to server up from my grafana.olddomain.uk:
location / {
proxy_pass http://127.0.0.1:3000;
}
I would like to proxy from my new domain (https://my.newdomain/grafana) to the old domain but have been hitting problems with the config:
location /grafana {
max_ranges 0;
rewrite ^/grafana/(.*)$ /$1 break;
proxy_pass https://grafana.olddomain.uk/;
proxy_ssl_server_name on;
proxy_ssl_trusted_certificate /etc/nginx/conf.d/trusted_ca_cert.pem;
proxy_set_header Host $host;
}
This is throwing an error cleared being served by Grafana:
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
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
So that seems pretty clear, I am using a sub folder now and need to change grafana.ini but that will break grafana.olddomain.uk.
What do I need in my newdomain location to get this working?
EDIT: curl response (following redirects) from https://my.newdomain.uk/grafana
> GET /grafana HTTP/1.1
> Host: my.newdomain.uk
> User-Agent: curl/7.54.0
> Accept: */*
>
< HTTP/1.1 301 Moved Permanently
< Server: nginx
< Date: Fri, 16 Apr 2021 17:39:13 GMT
< Content-Type: text/html
< Content-Length: 162
< Location: https://my.newdomain.uk/grafana/
< Connection: keep-alive
<
> GET /grafana/ HTTP/1.1
> Host: my.newdomain.uk
> User-Agent: curl/7.54.0
> Accept: */*
>
< HTTP/1.1 404 Not Found
< Server: nginx
< Date: Fri, 16 Apr 2021 17:39:13 GMT
< Content-Type: text/html; charset=UTF-8
< Transfer-Encoding: chunked
< Connection: keep-alive
< Cache-Control: no-cache
< Expires: -1
< Pragma: no-cache
< X-Frame-Options: deny
<

Answer 1

So after a lot of attempts at getting a sub path working I had to give up and set this up on root. This required splitting all the configurations up into separate sites.
location / {
max_ranges 0;
proxy_pass https://grafana.olddomain.uk/;
proxy_ssl_server_name on;
proxy_ssl_trusted_certificate /etc/nginx/conf.d/trusted_ca_cert.pem;
proxy_set_header Host $host;
}