Gunicorn + nginx - Ignoring EPIPE
If Gunicorn and NGINX are running on the same server, this could be a permission issue.
Check which user the Gunicorn server is running your application as with ps aux | grep gunicorn, then you can change the permissions accordingly.
Stop NGINX, and run the commands below
chown gunicorn_user_here.nginx /var/lib/nginx/tmp/proxy -vrm /var/lib/nginx/tmp/proxy/* -Rchmod 777 /var/lib/nginx/tmp -vStart NGINX and check the logs.