getting '502 bad gateway' error intermittently.

[shobhit mishra]

We are using nodejs,express,nginx for our app  and getting '502 bad gateway' error intermittently.Though we are unable to track this in pm2 logs, though nginx error log is showing:

   

recv() failed (104: Connection reset by peer) while reading response header from     upstream, client: xxx.xxx.xxx.xxx, server: somedomain.com, request: "GET /img/abc.png HTTP/1.1", upstream: "http://127.0.0.1:3000/img/abc.png", host: "domain.com", referrer: "http://domain.com/admin/"

andf nginx access log is saying:

"GET /url/abc.html HTTP/1.1" 502 723 "http://domain.com/admin/" "Mozilla/5.0 (X11; Linux i686) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/33.0.1750.117 Safari/537.36"