upstream timed out

nginx 1.4.6

 

Error on nginx access as below

 

2015/04/29 15:26:30 [error] 40620: *36947 upstream timed out (110: Connection timed out) while reading response header from upstream, client: 10.1.1.152, server: www.domain.com , request: "POST /administrator/index.php?option=com_installer&view=update&task=update.ajax HTTP/1.1", upstream: "fastcgi://127.0.0.1:9000"

 

Symptom:

 

• suddenly back to front page from joomla backend upon reloading page (rsult of clicking link)

Is this related to 10.1.1.152 (F5 LB) settings or something that I should configure on nginx?