Geoserver WM

CesiumJS
1

I have setup Geoserver on a computer and I am trying to use it with Cesiumsjs. I keep getting An error occurred in "WebMapServiceImageryProvider": Failed to obtain image tile X: 1 Y: 0 Level: 0. I have tried making Geoserver work use Cors but Geoserver crashes. I tested Geoserver with the WMS viewer https://wmsviewer-rodis.rhcloud.com and that worked. So I am wondering if I did something wrong with the code.
var viewer = new Cesium.Viewer('cesiumContainer');

// Add a WMS imagery layer
var imageryLayers = viewer.imageryLayers;
imageryLayers.addImageryProvider(new Cesium.WebMapServiceImageryProvider({
    url : ‘http://geospatial.scieron.com:8887/geoserver/border2/ows’,
    layers : ‘border2’,
    parameters : {
        transparent : true,
        format : ‘image/png’
    }
}));

// Start off looking at Australia.
viewer.camera.setView({
    destination: Cesium.Rectangle.fromDegrees(114.591, -45.837, 148.970, -5.730)
});