Thanks for writing in! Most probably you're running out of your server's allocated memory. First of all, try re-generating your permalink settings and see if that is related to your .htaccess file.
- Check your permalink settings (General -> Permalinks) and set
Postname save changes to re-create your .htaccess file.
Then try increasing your PHP Memory limit by editing your wp-config.php file which can be located under the root of your WordPress installation.
Add the following lines into that file.
define( 'WP_MEMORY_LIMIT', '512M' );
define( 'WP_MAX_MEMORY_LIMIT', '512M' );
You can add it before the line
/*That's all, stop editing! Happy Blogging. */
Check the following as well.
- Make sure that you're running at least PHP v5.6.x or later to avoid any WordPress related incompatibility issues. If you're not sure what your server configurations and settings are, install a plugin like WP-Serverinfo (https://wordpress.org/plugins/wp-serverinfo/) and check your server info by head over to Dashboard -> WP Serverinfo area.
- Check your
PHP Max Execution Time and set it for 300 for optimal usage.
Further, our troubleshooting guide here (https://theme.co/apex/forum/t/troubleshooting-builder-preview-warnings/14404).
Let us know how it goes.