Same issue here. I used the direct connection a lot and when I upgraded to 16.x it broke. I get the random messages, and usually when I toggle between encrypted and not encrypted it will eventually make a connection. I upgraded to the latest release, still broken... Sysaid blames the app "Ultra VNC", but it's the built in app provided by them.. The build date per the tool is from 2011? Perhaps it's out of date?