Why do I see the error "Zero Sized Reply Squid did not receive any data for this request." when attempting to login to the administrator?

Problem

I'm unable to log into my site administrator.  When I attempt to login to my Soapbox administrator, I am get the following error:

The following error was encountered:

Zero Sized Reply
Squid did not receive any data for this request.

Your cache administrator is #####.

Cause

You are likely trying to access your administrator while traveling via a public network at a hotel, coffee shop or other public place.

Solution

This is an issue with the network settings of the that network and, as such, there isn't anything we would be able to do about it from our end. However, if you do reach out to the system administrators of your network, this info may help them to understand what they need to do to address the issue:

Mis-configured proxies can interfere with request variables, headers, or session data in many cases, but only the proxy administrator will be able to identify the actual issue in this case. Since it's only occurring on your /administrator pages it likely is an issue specific to "POST" requests. As we block HTTP/1.0 POSTs to prevent attacks on our infrastructure, it's possible that mis-configured proxy is not correctly passing on the correct protocol version (HTTP/1.1) from the the browser.