The php.ini settings provided by your website host as defaults may not be optimal for use with WordPress and the Divi theme. If your global php.ini file has settings lower than shown below,  adjust them upward to these.  Your WordPress experience should improve. WordPress also wants to use ImageMagick, a PHP extension, to allow you to manipulate images.  The hosting company I use has ImageMagick installed, but it is not activated by default.  To activate it,  I need to use the last line in the following lines that go in the php.ini file:

post_max_size = 64M
memory_limit = 200M
upload_max_filesize = 64M
max_execution_time = 300
max_input_vars = 3000
extension =

WordPress also likes you to use the most recent version of PHP.  You should be able to change the version used by your host in the host’s control panel.  For more on WordPress settings, sign into your WordPress installation and choose Tools > Site Health and also check out Divi > Support Center.  The Divi > Support Center page will show the above recommended settings if your site is not already set up that way.  If all is good,  the System Status section will say: “Congratulations, all system checks have passed. Your hosting configuration is compatible with Divi.”

If you make all these changes and the Divi Builder won’t load, you probably have a plugin conflict.

Apparently when WordPress is using Imagick, uploads will sometimes fail with a general ‘HTTP Error.’  If that becomes a problem,  you can remove that line from the php.ini file.  If you have multiple WordPress installations on the same domain and imagick seems fine on some and not others,  you can add the following code to the functions.php file in your WordPress theme’s child theme:

function wpb_image_editor_default_to_gd( $editors ) {
$gd_editor = ‘WP_Image_Editor_GD’;
$editors = array_diff( $editors, array( $gd_editor ) );
array_unshift( $editors, $gd_editor );
return $editors;}
add_filter( ‘wp_image_editors’, ‘wpb_image_editor_default_to_gd’ );

This code overrides the php.ini setting for a single WordPress installation to use the GD image editor.