closestFacility.solve returns empty results

[Dirk_Vandervoort]

Here is the offending code (4.32)

const incidentGraphic = new Graphic({
    geometry: new Point({ x: -122.4079, y: 37.78356 })
  });
  
const incidentSet = new FeatureSet({
    features: [incidentGraphic]
  });
  
const facilityGraphic = new Graphic({
    geometry: new Point({ x: -122.4194, y: 37.7749 })
  });
  
const facilitySet = new FeatureSet({
    features: [facilityGraphic]
  });
  
const params = new ClosestFacilityParameters({
    incidents: incidentSet,
    facilities: facilitySet,
    travelMode: "Driving Time",
    returnDirections: true
  });

const networkServiceUrl = "https://route.arcgis.com/arcgis/rest/services/World/Route/NAServer/Route_World"

closestFacility
    .solve(networkServiceUrl, params)
    .then(result => {
        console.log("Closest facility result:", result);
    })
    .catch(error => {
        console.error("Error:", error);
    });

solve executes without error, however all the members of result are null. 

Why am I not able to find my closest facility?