Fb instant articles rss feed

My fb page isn’t able to get the articles from the rss feed. It was working fine 2 days back and I didn’t update the plugin. So I don’t understand what went wrong.

Here is the rss feed: https://emperorpost.com/instant_articles

Can you please verify if it is working fine? That the feed is generated properly?

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