Fatal error: Uncaught Error: Call to undefined function WP_Filesystem() in /mnt/web602/b0/93/526122393/htdocs/STRATO-apps/wordpress_01/app/wp-content/themes/Avada/includes/lib/inc/class-fusion-helper.php:86
Stack trace:
#0 /mnt/web602/b0/93/526122393/htdocs/STRATO-apps/wordpress_01/app/wp-content/themes/Avada/includes/lib/inc/custom-icons/class-fusion-custom-icon-set.php(89): Fusion_Helper::init_filesystem()
#1 /mnt/web602/b0/93/526122393/htdocs/STRATO-apps/wordpress_01/app/wp-content/themes/Avada/includes/lib/inc/custom-icons/class-fusion-custom-icon-set.php(142): Fusion_Custom_Icon_Set->__construct()
#2 /mnt/web602/b0/93/526122393/htdocs/STRATO-apps/wordpress_01/app/wp-content/themes/Avada/includes/lib/inc/custom-icons/custom-icons.php(34): Fusion_Custom_Icon_Set::get_instance()
#3 /mnt/web602/b0/93/526122393/htdocs/STRATO-apps/wordpress_01/app/wp-content/themes/Avada/includes/lib/fusion-library.php(105): include_once('...')
#4 /mnt/web602/b0/93/526122393/htdocs/STRATO-apps/wordpress_01/app/wp-content/themes/Avada/includes/bootstrap.php(23): require_once('...')
#5 /mnt/web602/b0/93/526122393/htdocs/STRATO-apps/wordpress_01/app/wp-content/themes/Avada/functions.php(51): require_once('...')
#6 /mnt/web602/b0/93/526122393/htdocs/STRATO-apps/wordpress_01/app/wp-settings.php(747): include('...')
#7 /mnt/web602/b0/93/526122393/htdocs/STRATO-apps/wordpress_01/app/wp-config.php(112): require_once('...')
#8 /mnt/web602/b0/93/526122393/htdocs/STRATO-apps/wordpress_01/app/wp-load.php(50): require_once('...')
#9 /mnt/web602/b0/93/526122393/htdocs/STRATO-apps/wordpress_01/app/wp-blog-header.php(13): require_once('...')
#10 /mnt/web602/b0/93/526122393/htdocs/STRATO-apps/wordpress_01/app/index.php(17): require('...')
#11 {main}
  thrown in /mnt/web602/b0/93/526122393/htdocs/STRATO-apps/wordpress_01/app/wp-content/themes/Avada/includes/lib/inc/class-fusion-helper.php on line 86