You may have an instance in which you must obtain new license files. For example, backups do not include the actual license files. So when you restore a backup, you must re-register your licenses. If you cannot locate your license files, you can obtain new ones on the Symantec Licensing Portal.
The basic product functionality for Symantec Messaging Gateway requires a single license. However, in addition to this license, you can obtain a license to enable Symantec Content Encryption. Content encryption lets you encrypt outbound messages for greater security and to track statistics for those messages through the Control Center.
Symantec Messaging Gateway stores the license serial numbers locally on the appliance. These serial numbers appear on the Administration > Hosts > Licenses page. As a best practice, you should write down these numbers.
A backup restoration does not affect your licenses. However, if you restore a backup on an unlicensed appliance, no serial numbers appear.