The Squid proxy 2.7 and later has a setting for “ignore_expect_100”. This is defaulted to “off”. The DyKnow Client and Monitoring service require this setting to be “on” to ensure proper communication with the DyKnow Server.
This can create the error: (417) Expectation failed. (InternalError: ProtocolError) returned from the server.
If you have the following line on your squid.conf
change the setting to:
This option is only available in Squid 2.7 or higher. Restart your squid proxy server to ensure the change is propagated.