hi
i'm using com version 2,5
and only use proxy feature only
so never use of full feature of endian but, i can block any https website.
if you cannot block it by content filtering, try to use "access policy"
create deny access rule and put "dotdomainname" in "destination"
webproxy filter is indeed not have that much database if you compare to google,
but you still can block it manualy