epoll_wait() reported that client prematurely closed connection, so upstream connection is closed too while sending request to upstream (no replies)

Hello,

We have a problem with nginx in a drupal site.
The images placed in the domain root are not visible in chrome, but in firefox for example, are fine.

This is the error in the nginx virtual host error log:

2015/04/15 03:59:26 [info] 3853#0: *104563 epoll_wait() reported that client prematurely closed connection, so upstream connection is closed too while sending request to upstream, client: xxx.xx.xxx.xxx, server: domain.com, request: "GET /sites/default/files/styles/slideshow__1170x450_/public/xxx.jpg?itok=M4PPaqtP HTTP/1.1", upstream: "fastcgi://unix:/tmp/php5-fpm.sock:", host: "domain.com", referrer: "http://domain.com/"

This is a server with nginx + php-fpm

I know this error was posted before but in russian.

Any ideas please?

Thanks,
pregunton.