Hi There,
Could you please enable WP_DEBUG
mode on your site by editing the wp-config.php file on your server which can be located in the root of your WordPress installation.
define('WP_DEBUG', true);
Then re-visit your page and see if you’re getting a PHP error message which explains your issue.
If you’re using a PHP version below 5.6.x, make sure to update your PHP version and re-test your issue.
Let us know how it goes.
Thanks!