The Elementor editor tries to load a JSON file that contains your global colors, typography, and layout options. The request runs through AJAX or the REST API. If the request cannot finish, Elementor shows a toast that says the site settings could not be retrieved.
Typical reasons include a blocked AJAX call, insufficient PHP memory, mismatched plugin versions, or corrupted data stored in the WordPress options table. Server security rules or SSL mismatches also stop the request from reaching WordPress.
When the request fails, the Site Settings panel stays on a spinner or appears blank. Other Elementor panels keep working because they do not depend on the same endpoint.