What’s happening?

The MIME type error means that the browser tried to load a JavaScript file (like /main.js or /assets/...), but the server responded with HTML (usually your index.html). This happens when Nginx can’t find the static file and falls back to index.html due to:

try_files $uri $uri/ /index.html;

This works well for your app’s routes (like /login), but should not apply to static files

Why it works locally but fails on Azure?

Azure Web Apps sit behind a reverse proxy, and sometimes their file serving logic can be a bit different. The fact that it works in IE but fails in Chrome is because Chrome enforces strict MIME type checks, while older browsers don't.

The fix:

You need to update your nginx.conf so that static files (JS, CSS, images, fonts, etc.) are served directly, and the fallback to index.html only applies to your app routes.

server {
  listen 80;
  server_name _;

  root /usr/share/nginx/html;
  index index.html;

  location ~* \.(js|css|png|jpg|jpeg|gif|ico|svg|woff|woff2|ttf|eot|otf|json)$ {
    try_files $uri =404;
    access_log off;
    expires 1y;
    add_header Cache-Control "public";
  }

  location / {
    try_files $uri $uri/ /index.html;
  }

  error_page 404 /index.html;
  error_page 500 502 503 504 /50x.html;
}