PHP writes all its errors into a log file which depends on your particular setup. It will typically be called error.log. It may be a good idea to ask your web host where you can check the contents of this file.

Besides this, it may be easier to have PHP just print out its errors on the screen (web page). This is disabled by default on many systems.

You can enable it in your php.ini file.

You may also enable it in your .htaccess File like this:

php_flag display_errors On
php_value error_reporting E_ALL

Finally, check your _advanced.php configuration file for the following:

/**
 * Do we want to display errors, even when not in debug mode?
 *
 * You are welcome to change/override this if you know what you're doing.
 * This is turned out by default so that newbies can quote meaningful error messages in the forums.
 */
$display_errors_on_production = true;

If in doubt, make sure this value is true and not overridden in _local.php.