I've configured a reverse proxy for images on a windows box however it is not working as expected.

First time I send a request to the server and I get the image with an http 200 as expected.
Second hit the request hangs for about a minute returning an http 304 as expected however I do not understand why the server hangs for about a minute? Next hit goes fine and then the following again hangs. I'm consistently getting the same results over and over again but I have no clue.

The same configuration on a linux box works correctly so I assume this is either a bug on the windows distribution or I might have to use a different config for some reason on the windows box?

Help will be greatly appreciated!

Thanks!