When widgets are not loading in Elementor most likely this is cause of lack of memory.
There are two places you need to increase memory.
1. In the WP Config file add this line:
define(‘WP_MEMORY_LIMIT’, ‘512M’);
2. In your PHP settings change PHP.ini
This can usually be done via Cpanel or by contacting your hosting provider.
You should increase this setting to the maximum available.