I am running into an issue, that I believe was documented here (https://trac.nginx.org/nginx/ticket/1005). Essentially, I am seeing alerts as our ELBs are sending 504s back to clients with no backend information attached, but when I look through our nginx request logs, I see that we "should have" sent them a 408. However, it appears that nginx is just closing the connection. We areby reverson - Nginx Mailing List - English