502 Bad Gateway

[Raphael Marot]

Hi all,

I have a simple setup with Nginx in front Apache, under debian wheezy 
(nginx for static content, apache for php)
Since the last Nginx update (1.1.17-2 via apt-get), every night after 
daily crons i have a 502 error (bad gateway) until i reload apache.
Everything was fine before.
I tried to reload apache after nginx in the logrotate daily task, but 
without effect.
In my logs i just have :

[error] 22332#0: *10804 connect() failed (111: Connection refused) while 
connecting to upstream

Where should i look at?

Thanks!