Nginx serves files at root (/) but not at subpaths (/admin, /user)

I have set up Nginx on my server to serve static files for a front-end application. The root URL (http://xxx.85.127.14/) correctly serves files, but when I try to access http://xxx.85.127.14/admin I get an ERR_EMPTY_RESPONSE error in the browser.

However, when I test locally it works:
curl -I http://localhost/admin

Server & Environment Details:

• OS: Ubuntu 20.04

• Web Server: Nginx

• Frontend Framework: React/Vue (if applicable)

• Deployment Directory:

  • /root/deployment/user/dist (for /) user

  • /root/deployment/admin/dist (for /admin)

Nginx Configuration (/etc/nginx/sites-available/default)

server {
    listen 80 default_server;
    listen [::]:80 default_server;
    server_name xxx.85.127.14;
    location / {
        root /root/deployment/user/dist;
        index index.html;
        try_files $uri /index.html;
    }

    location /admin {
        root /root/deployment/admin/dist;
        index index.html;
        try_files $uri /index.html;
    }


    location /api/ {
        proxy_pass http://localhost:5000/;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    }
}