Nginx site configuration disabling 301 rewrite for another site - redirect

Question

I currently have two enabled site configurations in nginx, let us call them old-site.example and new-site.example. There is no other site configuration active.
old-site.example should 301-redirect to new-site.example. This currently works well as long as the old-site.example configuration is alone. After adding the new-site.example configuration file, it does not redirect anymore.
oldsite.conf:
server {
listen 80;
server_name *.old-site.example;
rewrite_log on;
location / {
return 301 http://www.new-site.example$request_uri;
}
}
newsite.conf:
server {
listen 80;
server_name www.new-site.example;
charset utf-8;
location / {
#forward to application server
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_pass http://127.0.0.1:8080;
}
}
other configuration details:
JBoss AS7 as application server running behind Nginx 1.5.1

Answer 1

This was a DNS related error, sorry everyone.
Background: The ISP of the client managed to "smart redirect" the domain instead of using DNS. They basically scraped the new site on their servers and returned it via the old domain. I'm speechless.
If you ever have a problem like this, check DNS resolution before second-guessing your config.