I am impressed that you can do a lot with the server remotely to tweak its operation. I hoped that I wouldn't have to use these under the hood features, but I'm glad they are there. The machine, as well as all my remote machines, is running with dongles on the video ports to fake out a monitor.
Knowing the standard response is to say upgade to the latest, I don't understand why existing installations are failing, with no change on either side of version. That's why I call out some disconnect with the server information, unless the server information changes with versions, making old versions not able to interact with the server data. But I did upgrade already this host and client pair, grudgingly, because of the ripple effect across all the machine installations. But the result is the same. I cannot connect.
Today I cannot connect to a computer that I recently connected to. Usually this has been something malfunctioning with the RU server. Note that I can see the screen on the logged-in thumb-nail, but the full control connect won't complete.