error in cesium.js

I have run into a very strange problem. The following code works on one page, but not another.

All the Cesium related code is identical. The error occurs specifically on the viewer= line, but the actual error is in cesium.js version 1.64

The error is TypeError: e is null. I cannot specify a line number because all the code is on a single line.

This is using Firefox on windows 7.

viewer = new Cesium.Viewer(‘cesiumContainer’, {
terrainProvider: Cesium.createWorldTerrain(),
homeButton: false,
animation: false,
baseLayerPicker: false,
fullscreenButton: false,
geocoder: false,
homeButton: false,
infoBox: false,
sceneModePicker: false,
selectionIndicator: false,
timeline: false,
navigationHelpButton: false,
navigationInstructionsInitiallyVisible: false

Any help would be appreciated.