After ONTAP upgrade, backup of existing NDMP hosts or adding new hosts fails

Note: NDMP protocol refers to a backup application as a Data Management Application (DMA.) 

• Previously working NDMP backups fail after upgrading to ONTAP 9.10.1.
• Attempts to configure new NDMP backups also fail after upgrading to ONTAP 9.10.1
• The same types of failures can also occur if configuring new NDMP backups for an ONTAP 9.10.1 (and later) cluster (an upgrade from an earlier version of ONTAP is not required)
• The failed backups or configuration attempts are associated with connection errors between the DMA and the NDMP Server
  • On the DMA side, errors like this may appear:

NDMP connection to  host [NetApp hostname] failed.

• NDMP configuration, including authentication, is configured and appears correct
• The NDMP hostname or IP address in the DMA configuration corresponds to either a data LIF, or a LIF using a custom service policy
• For data LIFs, failed connections from the DMA are not logged to the ndmpd log
• For non-management LIFs using a custom service policy, the NDMP debug log may contain a single error corresponding to the failed DMA connection attempts: