"Client closed connection" when using nginx on Windows

[tima_121]

As part of a project I'm working on, I've been using nginx on Linux systems
for a while.
Currently I'm trying to run it on a Windows system.
When I send a request to nginx (using a browser) it fails, and I get this
error message in the error log:

2017/06/26 14:15:56 [info] 34092#16900: *1 client closed connection while
waiting for request, client: xxx.xxx.xxx.xxx, server: xxx.xxx.xxx.xxx:4322

Note that this message appears immediately upon making the request, not
after some timeout period.
Additionally, the nginx is configured to just return a 400 error code, so
nginx isn't trying to proxy to some external server.
I wasn't able to detect any problems in WireShark - SYNs being exchanged,
ACK returned, HTTP request, ACK, 2 more SYNs + ACK, then ~30 seconds later
the connection closes (FIN).

The relevant config section:
server {
		listen xxx.xxx.xxx.xxx:4322;
		location / {
			return 400;
		}
	}

Does anyone have an idea of why this happens?

Posted at Nginx Forum: https://forum.nginx.org/read.php?2,275134,275134#msg-275134