This occurs when there are no available licences. Try again later - in most cases you will be able to login once another user has logged out.
To view who is using the available licence(s) select the “Show licence information” link on the error message. This will open the Licence Viewer. Open the Modules section then your relevant program e.g. Elite. Below this will show the user(s) currently logged into PATGuard and on which PC. E.g. “LauraM on HM0008” where LauraM is the PC/network login and HM0008 is the PC / Server name.
It is possible that the program has crashed or not been shut down properly therefore has not released the licence. If the listed user(s) are no longer using the program then they need to log back into PATGuard and log out again to release the licence correctly. Your IT department should be able to assist here.