Problem load geoserver wms

good morning
I have created with geoserver I have created a group of layers that are seen correctly when I open it with open layers, but with cesium I am not able to visualize it. I did this code but it doesn’t show.
// Create the object that represents the Cesium view
var viewer = new Cesium.Viewer(‘cesiumContainer’);

// We create the layer for our WMS service
var wmsLayer = new Cesium.ImageryLayer(
new Cesium.WebMapServiceImageryProvider({
url :‘http://localhost:8080/geoserver/wms’,
layers : ‘CAIT-3099:Christ_M2’
})
);

// Add the layer to the map
viewer.imageryLayers.add(wmsLayer);
// Start off looking at CANARY ISLANDS.
viewer.camera.setView({
destination: Cesium.Rectangle.fromDegrees(
-18.50,
27.40,
-13.20,
29.60
),
});