Avia Layout Builder not loading

Hi, we’re having trouble getting the Layout Builder to load when we try to edit an existing page. When creating new pages, though the builder does load initially, it eventually gets stuck on loading as you try to save your progress.

We are getting the follow error in the Console: Failed to load resource: the server responded with a status of 404 (Not Found) /wp-admin/admin-ajax.php:1

Based on similar forum posts, we’ve tried the following things but have been unable to solve the problem:
1. update to the latest version of the enfold theme
2. disable plugins one by one and test builder
3. adding the following code (https://kriesi.at/support/topic/editor-avia-dont-work-with-new-version-of-wordpress/):
// disable for posts
add_filter(‘use_block_editor_for_post’, ‘__return_false’, 10);
// disable for post types
add_filter(‘use_block_editor_for_post_type’, ‘__return_false’, 10);

4. contact hosting provider to check if wp-admin/admin-ajax.php is being blocked by mod_security rules. Provider replied saying that there’s no blocking of any kind going on and sent us the following image [see private content]

5. We downloaded a copy of the site using the All-in-One WP Migration plugin and installed it locally. The builder didn’t give us any errors on the local install. Since we needed to add a new page to the site ASAP, we edited the site locally and then imported the updated site to the live site using the same plugin. The builder on the live site is still giving us the same 404 error.

Hope you can help us figure this one out.

Thank you!