Hi @echeng - I think it might be because you’re using Colab. I was using Gradient (and I’m assuming Ricardo might have been too).
According to the replies to this post, Voila may not work with Colab 
I tried to get Colab to work and was also having issues.
I’d suggest you download (the shortened version of) your notebook & .pkl file, launch a CPU instance in Gradient and try again over there.