Email enrollment of Symantec Encryption Desktop fails when you enroll a client using an IMAP account with Microsoft Exchange Server 2016/ 2013 Cumulative Update 2 (CU2).
To work around this issue, use MAPI or POP accounts with Microsoft Exchange Server 2016 and 2013 CU2 for email enrollment.
Symantec Corporation is committed to product quality and satisfied customers. This issue is currently being considered by Symantec Corporation to be addressed in a forthcoming version or Maintenance Pack of the product. Please be sure to refer back to this document periodically as any changes to the status of the issue will be reflected here.