I am facing weird issues and I am not able to debug the issue.
There are several applications I have deployed on aws ec2 instances with nginx and letsencrypt ssl certificates.

Websites are working fine on almost every device. One of the clients is using benq flat panel model rm7501k. None of the websites that I deployed is working on the panel.

Issues I have discoverd:

• for one php website -> html is loading but css is not loading

• for react applications -> frontend part is loading but not apis are being called.

• I have even tried to use ssl certificate from cloudflare (free version and proxied)

But other websites are working fine and I am not able to debug the network tab on the browser on that device as it is android based.

nginx config

server {
server_name  api.examplexx.com;

     location / {
         proxy_set_header X-Real-IP $remote_addr;
         proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
         proxy_set_header Host $http_host;
         proxy_set_header X-NginX-Proxy true;
         proxy_pass http://127.0.0.1:4003/;
         proxy_redirect off;
         proxy_http_version 1.1;
         proxy_set_header Upgrade $http_upgrade;
         proxy_set_header Connection "upgrade";

         proxy_redirect off;
         proxy_set_header   X-Forwarded-Proto $scheme;
         proxy_read_timeout 600;
         proxy_connect_timeout 600;
         proxy_send_timeout 600;
}

    client_max_body_size 250M;

  listen 80;
   listen [::]:80;

    }

I have tried to install the other browsers but not able to install because of firmware restrictions.

Is there any way to debug the issues.

Any suggestions or debug information will be appriciated.