Knowing the exact source of the issue on your website, decreases the time in witch the problem will be fixed.

Debugging is a simple built-in tool added by WordPress and in this documentation thread we’ll go through the steps needed to make debugging by yourself.

To turn on WP_DEBUG, simply go to your wp-config.php file and search for the following line: http://take.ms/GeLaF

 define('WP_DEBUG', false);

Simply replace this line with the following code:

define('WP_DEBUG', true);
define('ZN_FW_DEBUG', true);
define('WP_DEBUG_LOG', true );
ini_set('error_log', dirname(__FILE__).'/wp-content/debug.log');

Once you’re done replacing it should look like this: http://take.ms/Ikh6b .

The new error log will be added like the code suggests in  /wp-content/debug.log

In this debug.log file you should see any PHP background error you might have which would provide hints on how to fix any issue.

Note that there are problems that don’t appear in the debug.log and further investigation will be necessary.

An example of an error captured on the debug.log would be this:  http://take.ms/hfm0s