amazon web services – Nginx reverse proxy behind ALB


I have following configuration, it works really well if I put instance DNS name as server name.
But if I use the ALB DNS name as server_name, and if I try to access it with the ALB address, it just displays the default nginx page.

cat /etc/nginx/conf.d/tomcat.conf
server {
    listen 80;
    listen [::]:80;
    server_name tomcat-8554.us-east-2.elb.amazonaws.com www.tomcat-8554.us-east-2.elb.amazonaws.com;
    location / {
            proxy_redirect      off;
            proxy_set_header    X-Real-IP $remote_addr;
            proxy_set_header    X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header    X-Forwarded-Proto $scheme;
            proxy_set_header    Host $host;
            proxy_pass          http://localhost:8080;
    }
}

Any idea?