How to fix Fatal error: Allowed memory size of 67108864 bytes exhausted (tried to allocate 96 bytes) in

Once i visited my site and found it’s broken and shows following error:

Fatal error: Allowed memory size of 67108864 bytes exhausted (tried to allocate 96 bytes) in /home/globalre/globalrecruiters.com.ua/www/wp-content/themes/Avada/includes/lib/inc/class-fusion-settings.php on line 170

Let’s open wp-includes/default-constants.php and see default constants:

function wp_initial_constants() {
global $blog_id;

/**#@+
 * Constants for expressing human-readable data sizes in their respective number of bytes.
 *
 * @since 4.4.0
 */
define( 'KB_IN_BYTES', 1024 );
define( 'MB_IN_BYTES', 1024 * KB_IN_BYTES );
define( 'GB_IN_BYTES', 1024 * MB_IN_BYTES );
define( 'TB_IN_BYTES', 1024 * GB_IN_BYTES );

define( 'WP_MEMORY_LIMIT', '128M' );
/**#@-*/

// Start of run timestamp.
if ( ! defined( 'WP_START_TIMESTAMP' ) ) {
    define( 'WP_START_TIMESTAMP', microtime( true ) );

Now let’s change it and set WP_MEMORY_LIMIT to 128M.

function wp_initial_constants() {
global $blog_id;

/**#@+
 * Constants for expressing human-readable data sizes in their respective number of bytes.
 *
 * @since 4.4.0
 */
define( 'KB_IN_BYTES', 1024 );
define( 'MB_IN_BYTES', 1024 * KB_IN_BYTES );
define( 'GB_IN_BYTES', 1024 * MB_IN_BYTES );
define( 'TB_IN_BYTES', 1024 * GB_IN_BYTES );

define( 'WP_MEMORY_LIMIT', '128M' );
/**#@-*/

// Start of run timestamp.
if ( ! defined( 'WP_START_TIMESTAMP' ) ) {
    define( 'WP_START_TIMESTAMP', microtime( true ) );
}