I am developing a web application that allows users to upload files to a server. I am using NGINX as the reverse proxy and Gunicorn3 as the WSGI for the Flask app that handles the upload.

The NGINX error log gives the following error:

2020/04/07 01:08:46 [error] 3546#3546: *22 sendfile() failed (32: Broken pipe) while sending request to upstream, client: 98.225.23.249, server: 34.212.20.59, request:$

How do I resolve this issue?