Unable to find object the backup during the restore
Either the backup set chosen was not far enough in the past or the object did not exist in Active Directory.
Choose a backup set that may contain the object and is still within the objects tombstone lifetime. Tombestone lifetime is typically 180 days. Make sure the object did exist in Active Directory to begin with. For example printers are not by default automatically added to Active Directory.
For more information on determining the tombstone lifetime, see the below solution: