This message means that connection to lmgrd is lost.
Try to do the following on Sever PC:
1. Open Network and Sharing Center
2. Select the change adapter settings
3. Right click on the network adapter and select 'Properties'
4. Select the 'Configure...' button
5. Select the 'Power Management' tab
6. Uncheck 'Allow the computer to turn off this device to save power'
7. Restart License Server.