Ext is not defined, when using nginx

I am getting a weird issue on traccar.
My traccar runs absolutely fine when accessed directly through IP address on port 8082.
I am using nginx as reverse proxy and redirecting so that I can access it using subdomain and from port 80.
Here is the nginx config for reference.

server {
        listen 80 default_server;
        server_name subdomain.mydomain.com;        
       location / {
                proxy_pass http://localhost:8082;
        }
        location /api/socket {
                proxy_pass http://localhost:8082/api/socket;
                proxy_http_version 1.1;
                proxy_set_header Upgrade $http_upgrade;
                proxy_set_header Connection "upgrade";
        }
}

using IP:8082 it works perfectly fine
but using subdomain.mydomain.com it starts loading traccar even shows the title in the tab and loads all resources, but shows nothing.
On the UI console see below error. Nothing in nginx logs, that seems to be working all fine.

load.js:6 Uncaught ReferenceError: Ext is not defined
    at load.js:6
    at c (rocket-loader.min.js:1)
    at p (rocket-loader.min.js:1)
    at t.simulateStateAfterDeferScriptsActivation (rocket-loader.min.js:1)
    at Object.callback (rocket-loader.min.js:1)
    at t.run (rocket-loader.min.js:1)
    at x (rocket-loader.min.js:1)
    at Object.callback (rocket-loader.min.js:1)
    at t.run (rocket-loader.min.js:1)
    at rocket-loader.min.js:1

I checked in console and Ext is already loaded. So not sure what the issue is.
Looks like Ext is loaded but after it was being called for, which may be causing the error. But how come this happens only through the domain and not IP.

Any help would be appreciated.

Try clearing browser cache.

Already tried that a multiple times.