Thanks for asking.
Please follow up the steps below:
- Ensure everything is up to date according to our version compatibility list here. Please follow the best practices when updating your theme and plugins. Click here for more information.
- Go to X > Settings and click on the Clear Style Cache button.
- If you're using a CDN, please clear the CDN's cache and disable optimization services.
- Test for a plugin conflict. You can do this by deactivating all third-party plugins, and see if the problem remains. If it's fixed, you'll know a plugin caused the problem, and you can narrow down which one by reactivating them one at a time.
- Reset your htaccess file by renaming it to
.htaccess-bak. Then in WP Admin Menu, go to Settings > Permalinks and just click the Save Changes button.
- Increase the PHP Memory Limit of your server. Click here for more detailed information and how to increase the PHP memory limit.
- 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, you can check our troubleshooting guide here (https://theme.co/apex/forum/t/troubleshooting-builder-preview-warnings/14404).
If you still have problems kindly get back to us with the result of the steps above and URL/User/Pass of your WordPress dashboard using the Secure Note functionality of the post to follow up the case.