Why am I getting the error "Zero Sized Reply Squid did not receive any data for this request."

I'm unable to log into my site administrator.  I am getting the following error:

The following error was encountered:

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

Your cache administrator is #####.

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

This is an issue with the network settings of the hotel/coffeeshopt network. Unfortunately 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."