Dongle license is working for some time then the Software is running suddenly in Demo Mode

Dongle license is working for some time (>90 Minutes, usually some days / weeks). Then, suddenly the message “Software is running in Demo Mode” shows up.

Cause: energy-management of Windows shuts down USB-Ports to save energy.

Solution: 
Control panel -> Device manager -> Universal Serial Bus controllers -> USB-Root-Hub(s). 
In the tab “Power Management” switch off „Allow the computer to turn off this device to save power”
Do that with all USB-Hubs