404 not found error on Nginx

Question

I'm very new to AWS and Nginx.

When I get an access to my elastic ip address for web server EC2 instance, I get a 404 not found error.

How come it shows 404 not found error although I have uploaded files to the directory I set as root directory in nginx.conf file?

After I edited the nginx.conf file, I did reload nginx as well.

On EC2

$ ls sites/
LICENSE  README.md  css  fonts  index.html  js

nginx.conf

events {}

http {
    server {
        listen 80;
        server_name MY_IP_ADDRESS_HERE;
        root /sites/;
    }
}

Additional Information

I get a default nginx page when I set the root directory to "/usr/share/nginx/html/" in nginx.conf file, so the server is working ok.