If you get this kind of error in your nginx logs:
ERROR: *1754 upstream sent too big header while reading response header from upstream, client: X.X.X.X, server: XXXX
One solution that worked for me, was to set the fastcgi_buffers and fastcgi_buffers_size in nginx configuration file:
$ vim /etc/nginx/nginx.conf
Add the following params to your nginx configuration file:
fastcgi_buffers 8 16k; fastcgi_buffer_size 32k;
$ /etc/init.d/nginx restart
* This helped you ? Please share.