Minimwatch on Mac OS Catalina can't see Minimserver on Win 8.1

[usery]

Mac Minimwatch icon is grey, can't see Minimserver, see log below. UPnP control point app on same Mac can see Minimserver instance just fine.

Same subnet, no internal firewalls anywhere, anti-virus disabled on both hosts, no network blocking/filtering on LAN router.

What up?

Minimwatch 2.0.18 on Mac OS Catalina
IP address = 192.168.254.35
MinimWatch 2.0.18
Java™ SE Runtime Environment (build 12.0.2+10)
Java HotSpot™ 64-Bit Server VM (build 12.0.2+10, mixed mode, sharing)
Java runtime options: -Dfile.encoding=UTF-8
Platform default charset is UTF-8
System platform is macos
Active subnet is 192.168.254.0

Minimserver 2.0.12 update 182 on Win 8.1 - 64 Pro
IP address = 192.168.254.18
Win firewall: off
Network connection: Home

Thanks,
PS