ERROR SUBDOMAIN DOES NOT REDIRECT IN NGINX - nginx

Question

I have a domain like www.app.com and a subdomain like www.server.app.com
I just configure my sites-available, sites-enabled and hosts but my error is when I try to acced to subdomain, always redirect to domain. This is my code:
SERVER | SUBDOMAIN
upstream server.app.com {
server 127.0.0.1:3000;
}
server {
listen 0.0.0.0:80;
root /var/www/server.app.com/html;
server_name server.app.com;
access_log /var/log/nginx/server.app.access.log;
error_log /var/log/nginx/server.app.error.log debug;
location / {
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarder-For $proxy_add_x_forwarded_for;
proxy_set_header Host $http_host;
proxy_set_header X-NginX-Proxy true;
proxy_pass http://127.0.0.1:3000;
proxy_redirect off;
}
}
DOMAIN
server {
listen 80;
server_name app.com;
return 301 http://www.app.com$request_uri;
}
server {
listen 80;
#listen [::]:80 default_server ipv6only=on;
root /var/www/app.com/html;
index index.php index.html index.htm;
server_name www.app.com;
location / {
# try_files $uri $uri/ /index.php?$query_string;
try_files $uri $uri/ /index.php?q=$uri&$args;
}
location ~ \.php$ {
try_files $uri /index.php =404;
fastcgi_split_path_info ^(.+\.php)(/.+)$;
fastcgi_pass unix:/var/run/php5-fpm.sock;
fastcgi_index index.php;
fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
include fastcgi_params;
}
}
What is wrong, I have the same in other app and is good? thanks in advance