Squidguard behind parent proxy issues

[papa_joe]

I have pfSense 2.4.3P1 running with squid and squidguard package. I have the problem to not get any blacklist update, because the updater don't use the essential parent proxy. Also an external error page isn't displayed, because of ignoring the parent proxy. :(

How can I get the squidguard package work with a parent proxy?