After upgrading to Symantec Messaging Gateway 10.6.0, Delivery Status Notification messages encounter problems:
A change to the script engine of Symantec Messaging Gateway introduced bare line feeds in the Delivery Status Notification message headerss. These bare linefeeds are not RFC compliant and cause issues with some email environments.
This issue has been addressed in version 10.6.1 of Symantec Messaging Gateway. Customers are recommended to upgrade to this version to resolve the issue.