SpanVA Directory Sync (DSS)
Importing users via multiple Securlets as well as DSS Directory Sync can cause a user to have multiple email addresses under the same name.
One of the users could be listed as active while the other is inactive.
When importing the users, be sure to enable Import as active users during Securlet activation.
If users are already in CloudSOC as inactive, enabling this feature will activate them and allow email to work correctly.