Subdomains no longer work

[Peleke]

It worked sometime before that subdomains were accessible as they should be,
now they are not anymore but sadly I don't know why because I haven't tested
them with every change.
The config seems to be valid.
nginx is running on a Debian Wheezy server with PHP 5.5x, memcache and a few
other services.
I don't know why it serves the main domain as it should but no subdomains.
Thanks

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,244807,245173#msg-245173