DLS 4, Week 2, Residual Networks can't download as pdf

For this programming assignment, when I tried to download it as pdf, it shows the following error:

500 : Internal Server Error

The error was:

nbconvert failed: Pandoc wasn’t found.
Please check that pandoc is installed:

I tried other programming assignments, and some of them are working fine while others are not.

Maybe Coursera was having a technical problem.