Short version: if I manually start the UVNC Server service on Windows 10 x64, I cannot access it from a client. The client VNC Viewer of the same version reports "Server closed connection - The server running as application."
Details: Using UltraVNC 18.104.22.168 x64. It is set up to run as a service and works correctly. Sometimes I use the server locally; sometimes I access the server from another computer on my LAN with the UVNC viewer.
Several times I noticed that if I close the client and start using the server locally, the UVNC icon in the system tray is still colored yellow. List all Clients shows the client IP address (even though it's powered off) and I am unable to kill it. Kill All Clients doesn't work - no errors either. So I stop the service. This happens quite a lot - maybe 50% of the time.
Before getting up from the server, I re-start the UVNC service. After doing this, I can't access it with a client. I have to reboot the server before I can access it from a client again.
Plain vanilla install. No encryption. No MSLogon. No Java. Using the matching viewer. Only set a VNC Authentication password.