Hi,
Can you please do let me know what you mean by registered VC with both local/domain account? Does that mean you tried registering VC in VCNS with both local and domain account and still lookup service is not configurable? Are we using VCVA by any chance? Either use 'Administrator@vsphere.local' or 'root' for registering VC with VCNS and try registering the lookup service.Still no luck,please do post VCNS logs.