Release : 10.7.x
Component : Symantec Messaging Gateway
To change the sender email address for notifications, open SMG Control Center and navigate:
Content > Resources > Notifications > Select required email notification template > Modify 'Send from' under 'Sender/Recipient'
In this case it is 'Threat Defense - Message unscannable' notification template, but all of the notification templates have either [email protected] or [email protected] as 'send from' value by default, which should be changed.