Facebook made a change to their API on February 7th, 2018, which means that it’s no longer possible to display names or avatars for users who comment on your posts when using a regular Access Token. The only way around this is to obtain a “Page” Access Token which will give you permission to access this data in the API.
To obtain a Page Access Token first update the plugin to version 3.4 of the Pro plugin, or version 2.7 of the free plugin, and then click the “Log in and get my Access Token” button on the plugin’s settings page. If you’re using an older version of the plugin, or the PHP Standalone version, then you can obtain a Page token by following these directions.
Note: A “Page” Access Token should be long (as shown below) and not to be confused with a regular “App” Access token which is much shorter. Here is an example of a Page Access Token: