Can't display the User page in Autoposting settings

Hi,

After setting up the module, when going to Users in Autoposting settings (admin/config/social-api/social-post/facebook/users),
I'm getting a 'The requested page could not be found.'

And here is the error log message:

Uncaught PHP Exception Drupal\\social_api\\SocialApiException: "The Social Facebook Configuration is not valid" at ../web/modules/contrib/social_post_facebook/src/Plugin/Network/FacebookPost.php line 129, referer: https://mysite.com/en/user/1/edit 

Anybody have the same issue? What can be wrong?

Thanks for help.