Unable to launch Remote Control Session

I've run into an issue that started late last week where I am able to establish a connection to a remote computer using Connect on LAN, however when I try to start the Remote Control Session, it shows the Connecting... dialog for about 20 seconds and then that fails and kicks me back to the previous screen.

I can access the File Manager, so I know I have a connection with the remote computer, and nothing has recently changed regarding our network configuration. These remote machines have all been connected to previously without problem.

Additionally, this only seems to affect some of the machines at a given remote site. I've also run into situations where I am able to connect to a machine, but then after I reboot it, I am no longer able to start/re-start a remote control session.

Has anyone else run into similar behavior?

Joe