Please check for the following first:
Ensure everything is up to date according to our version compatibility list at https://theme.co/apex/forum/t/troubleshooting-version-compatibility/195. Just note that as of this time the latest version are
Pro 2.3.8, X 6.3.8, Cornerstone 3.3.8. 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.
If you're using a caching plugin, clear all caches including browser cache then deactivate your caching plugin and other optimization plugins.
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 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.
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.
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' );
7 Check php and mysql version. Wordpress requires
PHP version 7.2 or greater.
MySQL version 5.6
8 Make sure you have the latest verion of wordpres
Please confirm that you have done all this and if the issue persist kindly provide us your wordpress admin login in