We had been working on a project for a customer and things were progressing nicely. The customer was wanting to switch from their old Genesis based child theme to Divi. The designer he had been working with had designed a beautiful site, but for some darn reason the Visual Builder just wasn’t working. We reached out to Elegant Themes about this and this is what they had to say. We hoped this might help someone else: (If you’re on WP Engine, skip to the number 2).

Their first response was this:

Its possible you have a low value for the memory limit while using the WordPress Dashboard. (WordPress allows you to configure the frontend and backend memory limits separately). I recommend asking your web hosting provider if its possible to increase the memory limit for the backend only to at least 96MB (though 128MB would be preferable). Depending on your server’s configuration, adding the following two lines to your wp-config.php will set the appropriate memory limit for the frontend and backend:

/* Frontend */ define( ‘WP_MEMORY_LIMIT’, ’96M’ ); /* Backend */ define( ‘WP_MAX_MEMORY_LIMIT’, ‘128M’ );

We actually tried this and it worked up until recently when WP Engine apparently made a change.

There is currently a sticky post on the Support forums that reads:

We are aware of an issue that is preventing the Visual Builder from loading on all WP Engine accounts. If your website is hosted on WP Engine, you may notice that the Visual Builder fails to load (you will get a never ending spinner).

The problem is likely caused by the fact the WP Engine disables the WordPress Heartbeat everywhere except where they presumed it was necessary. The Visual Builder uses this core WordPress API to process Auto Saves, just like the normal WordPress editor does. Since the Visual Builder is not whitelisted in their system for disabling the WordPress Heartbeat, it fails to load.

As part of their techniques for managing resources in the Admin area of WordPress, WP Engine removes the Heartbeat API from most of the pages in the Admin area. The Heartbeat API has many purposes, but one of the primary purposes is in maintaining an edit lock while a particular user is editing a post. Thus, WP Engine leaves the Heartbeat API enabled on post edit pages only.

For the time being, you may still use the standard Divi Builder since WP Engine allows the WordPress Heartbeat when using WordPress post editor via post.php. We hope to have the issue resolved soon. We are looking into ways to disable Divi Builder Sync and Auto Saves for WP Engine customers, and whenever the WordPress Heartbeat is deregistered.

We are really sorry for the trouble this has caused. It’s not something that came up during our feature testing. We will find a solution, don’t worry