Make sure that you have setup proper application exceptions for Roon.exe and RAATServer.exe in all active firewalls and check your settings following the guide HQPlayer Setup.
As @BlackJack suggested, I would check firewall first, you can use these instructions to check the OSX firewall. You mentioned you have McAFee, is it possible that your McAFee firewall settings were reverted by an update? Can you temporarily try disabling McAFee as a test?
Step 1 : In order to connect to HQPlayer using any address other than localhost or 127.0.0.1 , you must enable the “Allow control from network” feature in HQPlayer. This is the globe icon on the far right hand side of the HQPlayer toolbar
Is the Mac server hosting both Roon and HQPlayer? If so, you’ll want to specify localhost.