The V-Ray license server (OLS) shows the status of your V-Ray licences, and is the same for whichever V-Ray product(s) you have.
Go to localhost:30304 in your web browser to find the licence server if it is installed on your computer.
Licence types will be shown as blocks in the main area. Clicking on these blocks will show the total number of licences, those currently 'available' and those already 'in use'.
When loading V-Ray in your application, a 'Failed to checkout V-Ray GUI license' can indicate that either the licence server (below) is not running, the correct account has not been signed in to, or that all licenses are already in use.
