This can occur if the Flexnet licensing service is not running.

For DraftSight license (Standalone) to work correctly there are few services that need to keep running on machine. If those services are not running then you may face issues in using the license. Please follow the steps below to resolve the problem: 

1. Go to Windows ‘Control Panel’ > ‘Administrative Tools’ > ‘Services’.

2. scroll down until you find "FlexNet licensing service 64" 

3. Double click on it and change the dropdown to "Automatic"