Sometimes i thappens that SmartConde VNC Manager fails to activate. In that case follow steps below to fix issue with licensing:

  1. Open cmd.exe and change directory to:
    • Enterprise Edition: C:\Program Files\SmartCode Solutions\VNC Manager (Enterprise Edition)\
    • Standard Edition: C:\Program Files\SmartCode Solutions\VNC Manager (Standard Edition)\
  2. Run the following command: vncmanager.exe /licdev
  3. You will be prompted to enter a serial number. You must complete this step. After that the application will close.
  4. Start SmartCode VNC Manager normally via the start menu shortcut.

Source: SmartCode Knowledgebase