VMware Cloud Director 10.6
This issue occurs if the portgroup name for the optional vcNoneNetwork parameter is part of a distributed switch which is located under a folder in vSphere and the distributed switch is not located at the root Datacenter level.
This is a known issue affecting Cloud Director.
To workaround the issue register the vCenter without customising the vcNoneNetwork.
Alternatively if a custom portgroup must be used, provide a portgroup from a distributed switch located at the root Datacenter level and not under a folder in vSphere.