In order to enable debug mode in Wordpress first go to cPanel and open File Manager. Navigate to your domain's root folder and open wp-config.php. Find a line that looks like:

define( 'WP_DEBUG', false );

And change it to:

define( 'WP_DEBUG', true );

Now your website will show you what's wrong with it. After you are done debugging, don't forget to set it back to:

define( 'WP_DEBUG', false );

to make sure nobody will see your website errors, warnings or other sensitive information.