When the drag and drop feature for widgets in WordPress is not working, it is usually caused by conflicts between plugins, themes, or outdated JavaScript files. To fix this issue, clear your browser cache, disable conflicting plugins, and try switching to a default theme. Also, make sure WordPress, themes, and plugins are updated to their latest versions. If the problem continues, use the Classic Widgets plugin or disable the block-based widget editor to restore the traditional drag-and-drop interface.