Hello there,
Thank you for writing in.
With the change in facebook graph API to version 2.7 the share count that we are using is no longer supported due to which the counts are appearing zero but we have already released an update of a plugin with this bug fix. Have you updated the plugin to version 4.1.8? If yes and still the counter is not working then please create a facebook APP and enter the facebook APP id and facebook APP secret in the miscellaneous settings then the counter should work fine.
But if you have enabled the cache please clear the cache after entering the APP id and APP secret.
Thanks