When I enter https://cecilshub.com/ on https://www.sharedcount.com/ it shows 20 instead of 50.
In any case, the reason is probably the following: to get the Facebook counts, a “Facebook app” is required. Every Facebook app has a limit in how many counts it can retrieve per day. As all free plugin users use the same app, it can happen that the limit got reached for a specific day. If you wait for a while, the counts will probably show.
In this plugin https://www.ultimatelysocial.com/usm-premium/ we implemented a more reliable way: there you can enter the details of your own app which you created on Facebook (it’s easy to set up), so you don’t have to share the app with others, and therefore also won’t reach the app limits.