On new HyperScale X installations, NDMP backups may fail with connectivity issues if the data interface pairs (DIPs) are not configured in the backup network. This is because the backups retrieve the IP of the storage pool instead of the data protection network.
This is an expected behavior with the HyperScale X software. When you configure a dedicated backup network using DIPs, the NDMP backups will complete successfully. For more information, see Configuring a Dedicated Backup Network Using Data Interface Pairs.