This article will guide you on how to fix #Horde webmail 'Zero sized reply squid #error' by making changes to the system configuration file of #Apache. This error occurs in webmail in Plesk after the upgrade of the Plesk version.
#Squid is a caching and forwarding #HTTP web 3proxy. It has a wide variety of uses, including speeding up a web server by caching repeated requests, caching web, DNS and other computer network lookups for a group of people sharing #network resources, and aiding security by filtering traffic.
To fix this error:
1. Try to add to squid.conf an option:
and restart squid.
2. Put the website to Proxy Exception.