Hey @tony,
I just tried and it worked. Can you try following these exact steps as I did and let me know if it works for you.
In terminal:
git clone https://github.com/zoom/sample-app-web.git
cd sample-app-web/CDN
npm install
npm run start
You should see this
If this does not work, can you send me a link to your code on github and I will try to debug.
Thanks,
Tommy