Relevant versions: ALL
When McAfee AV 8 or newer is installed, you must add the Symantec DLP application to the permitted list of processes for sending out mail. The executable file to add is "java.exe".
Otherwise, McAfee will not allow SMTP communication between Enforce (running within Java) and the SMTP Server.
Note: It's possible other issues could result in the inability to send out emails from the Enforce Server. If this solution does not resolve your issue, please contact Technical Support.