KB23633 - What happens to the license clients when the Enterprise License Server fails and is not brought back up online for more than 10 days?

This article explains the behavior of both the license server and license clients, when the server goes offline for more than 10 days.

If an Enterprise License Server has been down for more than 10 days and is powered back up, the behavior is as follows:
 

• It will reclaim all the leases, which were leased to its clients.
• Independently, the leases on the client devices will expire after 10 days, as they are unable to renew them due to ELS being down.  
• When they are able to connect to the ELS, all the leases will be renewed;  the configuration of the client on the ELS does not get zeroed out and only the actual allocation is returned to the license pool at the server.

The whole point of having license lease expiration is to allow a client to function, in the event that ELS goes down for any reason. The 10-day lease expiration allows license clients to function in the absence of the ELS.

Note: You must always backup ELS configurations, by exporting the system and user configuration files.