0xe0000f23 - The Backup Exec server cannot connect to the Exchange Database Availability Group. The Backup Exec Agent for Windows must be installed and running on all nodes in the DAG. Right-click on the Exchange DAG and select the 'Properties' option. Ensure that the latest version of Agent for Windows is installed and running on all physical nodes.
Debug log shows the following errors:
BEREMOTE: - ndmpConnectEx: All attempts to connect to 'DAG' failed
BEREMOTE: - ndmpConnectEx: failed to connect to 'DAG'
BENGINE: - DSEnumerator returned error 0xe0000f23.
BENGINE: - ERROR: Failed to EnumerateEntitiesAndCreateBSDList
The issue is resolved in Backup Exec 21.3 update
Workaround:
Manually select the Individual Microsoft Exchange Mailbox Database resources in the backup selection instead of selecting the top level DAG or sub-level Microsoft Information Store resource.