I have similarly "Eset livegrid cannot be reached." EP 8.1 and Eset Endpoint Security 8.1.2031.0 This happens on random computers with the same policies and Firewall settings. We use eset proxy on squid. As we have noticed, livegrid does not go through the proxy, but directly. Firewall rules pass port 53535 TCP/UDP on required IP (support.eset.com/en/kb332-ports-and-addresses-required-to-use-your-eset-product-with-a-third-party-firewall) - Reputation database (ESET LiveGrid), Web control/Parental Control, Antispam module.