Termination of Support for mail level backups using MAPI Protocol on MS Exchange 2013 with Cumulative Update 23 or above installed.
MAPI backup mode, (Messaging Application Programming Interface), is a Microsoft technology used by the backup software to enable MS Exchange Server 2013 mail level backups and restores.
Because of limitations and functional issues with Microsoft Exchange 2013 Cumulative Update 23 or above, MAPI backups will stop working.
To avoid issues with Microsoft Exchange 2013 mail level backup and restores, we recommend you change the backup method from MAPI backup EWS (Exchange Web Services).