10054: An existing connection was forcibly closed by the remote host

[madvas]

8712#14268: *2060 WSARecv() failed (10054: An existing connection was
forcibly closed by the remote host) while reading response header from
upstream, client:0.xx.xx.0 

Can any one help me on this please. 
I have site A , site B. 
Site B is front end with nginx... 
I am getting this error 10/3 times of request.

Posted at Nginx Forum: https://forum.nginx.org/read.php?2,267564,267564#msg-267564