Connecting Facebook Instant Articles: Empty Content

Hello all,

I tried to connect my post to Facebook instant articles via the link generated by this plugin (https://www.flyasia.co/instant_articles). Yet, Facebook said that I have empty content for my articles.

Plug-in Setting: https://imgur.com/URD7UpW
Facebook’s error page: https://imgur.com/DrO5n84
Article page: https://www.flyasia.co/2018/08/10/hkg-courtesy-channel-%E9%A6%99%E6%B8%AF-%E7%A6%AE%E9%81%87%E9%80%9A%E9%81%93/

But indeed I have content for the article. I just wonder why it comes up with such an error… Any idea on how to fix it?

The page I need help with: [log in to see the link]