This error occurs when Elementor cannot locate the standard content injection point within your theme. The page builder requires the active theme to utilize the `the_content()` function. Without this specific function call, Elementor fails to identify where to render the editor interface. The issue also arises if a Theme Builder template lacks the “Page Content” widget. Additionally, conflicts with permalink structures or attempts to edit dynamically generated pages like the Posts Page trigger this warning. The editor essentially refuses to load because it cannot find a valid container for your design.