The Unity Toolbox does not come standard with 20-sim. It has to be purchased separately. If you have purchased the Unity Toolbox you will receive a license key that will enable the toolbox in 20-sim.
Without a valid license, the Unity Toolbox plug-in will stop the simulation and present an error message in the 20-sim Editor:
Message: Could not find Unity toolbox license.
Error Message when you do not have a license for the Unity Toolbox.