Hi,
Looks you recently installed SSL certificate at your site.
The plugin stores comments directly to Facebook with URL and without SSL, URL will start with http whereas after SSL, URL will start with https. Means a different URL will not have previous comments.
There is an option in the plugin to show comments before SSL. You can turn on or if you want to start comments with https then you need to scrape your URL by Facebook so that Facebook crawl your new URL and show comments box for new comments.
We just scraped your given URL and comments box is now showing on the post. You need to do it for every post for immediate result.
Here is our post how to use Facebook tool to scrape URL
https://wordpress.org/support/topic/the-plugin-shows-facebook-notice-for-eu-you-need-to-login/
Also your site is having many issues and warnings in console. You need to address them for smooth integration of the Facebook comments.
Hope it will help.
Regards
