What could be the problem here?

I have problems rendering plotly charts on nbviewer.

So I tried the following :

I grabbed a sample notebook online with plotly charts that have no problem rendering on nbviewer: Jupyter Notebook Viewer

I copied it and only added a simple plotly chart of my own at the bottom of the notebook to test it on nbviewer. Now, out of a sudden none of the charts render on nbviewer. Jupyter Notebook Viewer

Does anybody have an idea what could be wrong with it?