Error log: upstream timed out (110: Connection timed out) on Nginx

Please... I need help!!! My script don't works! My script in php only load for serveral time and afterwords appears that message:

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An error occurred.

Sorry, the page you are looking for is currently unavailable.
Please try again later.

If you are the system administrator of this resource then you should check the error log for details.

Faithfully yours, nginx.

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In /var/log/nginx/nginx_error.log show me that error:


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[error] 2019#0: *1 upstream timed out (110: Connection timed out) while reading response header from upstream, client: x.x.x.x, server: localhost, request: "GET /sistema-10-reais/ HTTP/1.1", upstream: "fastcgi://unix:/var/run/php5-fpm.sock", host: "x.x.x.x.x"
root@zash:/var/log/nginx#
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when is x.x.x.x is IP.

I am using nginx on ubuntu 14.04.