I had a similar issue getting Fedora 20, Nginx, Node.js, and Ghost (blog) to work. It turns out my issue was due to SELinux.
This should solve the problem:
setsebool -P httpd_can_network_connect 1
Details
I checked for errors in the SELinux logs:
sudo cat /var/log/audit/audit.log | grep nginx | grep denied
And found that running the following commands fixed my issue:
sudo cat /var/log/audit/audit.log | grep nginx | grep denied | audit2allow -M mynginx
sudo semodule -i mynginx.pp
References:
http://blog.frag-gustav.de/2013/07/21/nginx-selinux-me-mad/
https://wiki.gentoo.org/wiki/SELinux/Tutorials/Where_to_find_SELinux_permission_denial_details
http://wiki.gentoo.org/wiki/SELinux/Tutorials/Managing_network_port_labels