Thanks for writing in!
As we don't have access to your setup so can't confirm what exactly happening. Would like to give you few troubleshooting to check if that helps.
Please check for the following first:
1. Ensure everything is up to date according to our version compatibility list at https://theme.co/apex/forum/t/troubleshooting-version-compatibility/195. Please follow the best practices when updating your theme and plugins. See https://theme.co/apex/forum/t/setup-updating-your-themes-and-plugins/62 for more details.
2. Clear all caches including browser cache then deactivate your caching plugins and other optimization plugins.
3. If you're using a CDN, please clear the CDN's cache and disable optimization services.
4. Test for a plugin conflict. You can do this by deactivating all third party plugins, and seeing 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.
6. 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.
7. Contact your host to increase your allocated memory or do it yourself by adding this code in your wp-config.php
define( 'WP_MEMORY_LIMIT', '256M' );
define( 'WP_MAX_MEMORY_LIMIT', '512M' );
In case the issue persists, would you mind providing us with login credentials so we can take a closer look? Please provide following information:
Set it as Secure Note
* Link to your site
* WordPress Admin username / password
* FTP credentials
All the best!