I can't seem to get the Solarwind Event Log Forwarder to send any information to our Kiwi Syslog. This is a new setup on a closed system with no access to the Internet. The machines are running Windows 10 v1703 and Server 2012 R2.
Internet connectivity shouldn't be required for the event log forward tool, it's a free tool so it shouldn't be checking for license manager either. Anytime I've ever had issues getting the event forwarder to work, it's been a permissions or firewall issue. It installs as a service for the local system account.
If you want to test connectivity, see if you can find a copy of Klog lurking around somewhere, it's a command prompt utility that you can use to send a message to a syslog server.