"The address ##.##.##.## did not belong to any known host"
If it's not possible to modify the setting in the UI, contact Broadcom Support and note this Article ID (325514) in the problem description. For more information, see Creating and managing Broadcom support cases.
For more information on editing DNS settings in VMware Cloud Director, see Edit the DNS Settings of an Organization Virtual Data Center Network in the VMware Cloud Director Tenant Portal.