If you try to enable a Flexlm service and get the error message "VD is starting, please check vendor daemon's status in debug log". The error can be caused by a few things. What worked for us was this process. 

1) Make sure you have the latest version of LMTools installed. Currently version Download here: https://knowledge.autodesk.com/customer-service/network-license-administration/get-ready-network-license/download-the-network-license-manager 

2) Check services are configured appropriately 

  • Click Start > type services.msc > press Enter 
  • Look for the LMTOOLS service in the list (the service name is shown in LMTOOLS > Config Services > Service Name) 
  • Right-click on the service > Properties 
  • In the General tab, make sure the service Startup type is set as Automatic 
  • In the Log On tab, make sure that Local System account is selected 
  • Click Apply and OK Try to launch the server again.

 Here's the knowledge base article from Autodesk: https://knowledge.autodesk.com/search-result/caas/sfdcarticles/sfdcarticles/Error-VD-is-starting-please-check-vendor-daemon-s-status-in-debug-log-when-starting-service-on-LMTOOLS.html