Varnish connection reset error

[Julian De Marchi]

Hey!

I'm having an issue with Varnish 4.0. I have Varnish setup as my 
front-loadbalancer to my pool of web servers. I'm having an issue with 
Varnish were the pool of web servers return a 200 for a URI, but FF 
returns "The connection was reset". When I dial direct to a server in 
the pool for the domain, it works as expected. Below is the Varlishlog 
output for the request.

http://pastebin.com/ztbDCzGB

Here is my startup command for Varnish from systemd.

"ExecStart=/usr/bin/varnishd -a 0.0.0.0:80,[::]:80 -f 
/etc/varnish/default.vcl -T 0.0.0.0:6082 -s malloc,3G -u nobody -g 
nobody -p thread_pools=2 -p thread_pool_min=400 -p thread_pool_max=4000 
-p thread_pool_add_delay=2 -p http_max_hdr=1024 -S 
/etc/conf.d/varnish.secret -F"

I know that the http_max_hdr is rather large, but that solves a bug I 
had with a site which produced a massive HTTP header.

I'm basically after any troubleshooting steps I can take to diagnose 
this issue? I know it lie within Varnish, and I bet it's just me 
forgetting a "config option" somewhere.

Thanks in advanced!

--julian