"Failed to checkout V-Ray gui license" error?

Failed to checkout V-Ray gui license error indicates a problem with V-Ray's interface license’s availability. If you get such error - check the topics below, relevant to your license setup:

 
  • Check if you have the license server installed. If the license server is working correctly, you should be able to see your licenses when you open an internet browser on the license server computer and navigate to its status page - http://localhost:30304
 
  • If you use online licensing (obtain the license over the internet) - you need to be logged in with your ChaosGroup username in the license server menu. Make sure you're using the username that's associated with your purchased license or a trial license. If you're logged in with the wrong username - navigate to "Online licensing" button->Deactivate to log off. To log in with the correct account - click on "Online licensing" -> Enable
 
  • If you have your license on a hardware USB dongle - make sure the dongle is plugged in and the dongle drivers are installed
 
  • If you obtain your V-Ray license from a license server on another computer - make sure your operating system's firewall or the firewall on the license server computer is not blocking TCP port 30304. You can test by trying to navigate in your browser to http://IP_Address:30304 - where "IP_Address" is the IP address of the computer with the license server installed. You should be able to access the status screen of the license server.
 
  • Check your license settings - they should point to the computer with V-Ray license server installed. Use "localhost" or "127.0.0.1" if that's the computer you're working on currently.
 
  • If you share your license with your colleagues - make sure that the license is not already engaged by someone else. Navigate in your browser to http://IP_Address:30304 - where "IP_Address" is the IP address of the computer with the license server installed. Click on the box with the name of your license and check if there is a free license. You can see who is engaging the licenses by clicking on the blue number of engaged licenses.