When the Messaging Gateway (SMG) license expired, message filtering stops and the SMG appliance deliveres messages unfiltered. When the SMG system is given a new license without restarting the MTA service or restarting the appliance, SMG will continue to deliver messages unfiltered until the appliance or MTA service is restarted.
When the filtering engine fails its first license check following license expiration, it signals the MTA that the license has expired and no messages should be scanned. The MTA does not send new messages to the filtering engine for scanning and does not, itself, check license status. This means that once filtering is disabled, it is not re-enabled until the MTA and filtering engine are restarted with an updated license.
This is a known issue and will be addressed with a future release.
Restart the SMG appliance after applying a new license to an appliance whose license had previously expired.