You may experience this issue when using Microsoft Remote Desktop feature in conjunction with LogMeIn.
To solve this issue, reboot the host computer.
If this fails to resolve the issue, re-install LogMeIn while physically sitting at the host computer.
You may see this message in LogMeIn Rescue when the computer you are connecting to goes into a mode which cannot be accessed while Rescue is running as an application. Example of this would be if the computer is set to lock itself after a certain period of inactivity.
You can prevent this by running Rescue as a system service, which is an option you initiate directly before clicking Launch Remote Control.