1. A concise explanation of the problem you're experiencing.
I am a new cesium user and have been reading an implementing the code given in the workshop. Initially there was no problem in loading the cesium viewer using the code given in APP.JS but now barring cesium viewer rest all is visible.
Kindly adhere to this problem asap.
2. A minimal code example. If you've found a bug, this helps us reproduce and repair it.
3. Context. Why do you need to do this? We might know a better way to accomplish your goal.
4. The Cesium version you're using, your operating system and browser.
version:1.38 browser: chrome OS: Windows 8.1,8GB RAM,i5 processor