Nothing shows on profile page

Have you configured your Facebook account for the domain of your WordPress administrative interface?

1. Visit the apps section of the Facebook developer site
2. Select the application associated with your WordPress account.
3. Enter your app’s domain: e.g. example.com
4. In the Select how your app integrates with Facebook enter the URL of your homepage: e.g. https://example.com/
5. Save changes.

Thank you, that solved it.

That really should be included in the list of prerequisites as otherwise there’s no indication whatsoever that that step is necessary.

It would also be much simpler if the authentication could happen from the Social Publisher page rather than having to go through the user profile too, which just lengthens the process unneccessarilly.

Thanks

Social Publisher page is accessible to site administrators. Edit profile page is available to site authors. A common use case for larger sites is a WordPress user capable of writing a post but not managing the site. Extending the profile page locates Facebook features for the author alongside other information possibly used to represent the author on the site and only requires the viewer to have permission to edit his own profile.

In the Select how your app integrates with Facebook enter the URL of your homepage: e.g. https://example.com/

I can’t find this option

That’s because the website is different now.
In my app dashboard on the Facebook developer page I clicked “Settings”, then “Add Platform”. After selecting “website” I added its URL in the new apposite box, then in the “App Domains” box I entered the URL without “https://www”.
Fine, that worked for me! Now I’ve got the options to connect a Facebook account in the profile settings.