If you had recently moved your WordPress website to Https/SSL, all your Facebook Comments must be lost. Don’t worry, you can recover Facebook Comments by installing Facebook Comments Moderation add-on.
Facebook App ID and Facebook App Secret are mandatory to recover Facebook Comments and for Recent Facebook Comments functionality to work. You can save these in the corresponding options in Settings section. For more details on how to get these, click on the (?) icon before each option.
Recent Facebook Comments and Recovered Facebook Comments will only be saved for a particular webpage only after someone posts a Facebook Comment on that webpage. This is when the add-on fetches the relevant comments for that webpage and you would be able to moderate the fetched comments in Recent Facebook Comments and Recovered Facebook Comments sections at add-on options page.
You can set the default status of Recent Facebook Comments using Default status of the comments to be displayed in Recent Facebook Comments widget option. You can change the status of comments manually from Recent Facebook Comments section. Only the approved comments will appear in Recent Facebook Comments widget that you can enable from Appearance > Widgets page in admin area (See screenshot below)
You can choose how many comments to display from the total fetched comments in database in Recent Facebook Comments and Recovered Facebook Comments sections using Number of comments to display in ‘Recent Facebook Comments’ section and Number of comments to display in ‘Recovered Facebook Comments’ section options, respectively.
To recover the Facebook Comments lost after moving to Https/SSL, enable Recover Facebook Comments (if moved to SSL) option. Facebook Comments won’t be recovered without enabling this option. But remember, Facebook Comments will be recovered for a particular webpage only after someone posts a Facebook Comment on that webpage.
To show the recovered Facebook Comments at frontend for a webpage, enable Display recovered Facebook Comments at the webpages option. Only the approved comments will appear at frontend. You can change the status of recovered comments from Recovered Facebook Comments section at add-on options page