One possible reason for this is that something may be blocking the browser from accessing the JavaScript file generated by Divi Booster. The JavaScript file contains the code needed to make certain features works so, if the browser can't access it, these features won't be applied to your site.

The JavaScript file is located at:

https://www.YOURSITE.com/wp-content/uploads/wtfdivi/wp_footer.js

If you browse to this URL (replacing www.YOURSITE.com with your own domain name) you would normally expect to see a file containing JavaScript code. If something is blocking access to this file, you will instead get a 403 Forbidden error page with the message:

Forbidden

You don't have permission to access /wp-content/uploads/wtfdivi/wp_footer.js on this server.

Here are possible methods for resolving this error:

Method 1: Allow Access to the wp_footer.js File

One way to solve it is to figure out what is blocking access to the wp_footer.js file.

This isn't actually an error in Divi Booster. When Divi Booster is installed on a basic Divi / WordPress installation, the file will not be blocked.

However, some security plugins (e.g. WordFence) and server configurations may disallow access to JavaScript files within the /wp-content/uploads/ folder by default. While the details of how to do this will vary depending on what is applying this restriction on your site, the solution is to update the configuration to either allow access to either all JavaScript files from within /wp-content/uploads, or better yet to create a rule specifically allowing access to the /wp-content/uploads/wtfdivi/wp_footer.js file.

Once this is done, you should be able to browse to the wp_footer.js file URL and correctly access the JavaScript code. At this point, the Divi Booster features should be working correctly again.

Method 2: Enable Inline JavaScript

If for some reason you are unable to track down the cause of the blocked access, there is a way to bypass it from within Divi Booster. In the Divi Booster settings, you'll find the following option:

Developer Tools > Generated JS > Use inline JavaScript

Enable this option and save. Now Divi Booster will include the JavaScript code directly within your site's HTML pages, rather than loading it from the separate wp_footer.js file. This means the features should work, despite the blocked access to the wp_footer.js file.