Backups to Data Domain fails with “the user has insufficient access rights. Err: 5075”

Challenge Backup or Backup Copy jobs targeting a Dell EMC Data Domain repository fail with the following error: Error: Failed to call RPC function 'DDBoostFcIsExist': Failed to connect to storage. Storage: , User: . the user has insufficient access rights. Err: 5075. Rescan operations for a Dell...