404 page not working with permalink: pretty using GitHub Pages + Jekyll

Question

In my config.yml I have permalinks set to pretty:

permalink: pretty

When I do this, my 404.html page is no longer showing up on my website (hosted on GitHub pages) when there is a 404 error. How do I fix this?

user_5374560 · Answer

What you need to do is add this in the front-matter of your 404.html file:

---
permalink: /404.html
---