Fatal error: Uncaught TypeError: call_user_func_array(): Argument #1 ($callback) must be a valid callback, function "_wp_register_default_icon_collections" not found or invalid function name in /mnt/web718/a2/30/510219830/htdocs/relaunch/wp-includes/class-wp-hook.php:353
Stack trace:
#0 /mnt/web718/a2/30/510219830/htdocs/relaunch/wp-includes/class-wp-hook.php(377): WP_Hook->apply_filters()
#1 /mnt/web718/a2/30/510219830/htdocs/relaunch/wp-includes/plugin.php(523): WP_Hook->do_action()
#2 /mnt/web718/a2/30/510219830/htdocs/relaunch/wp-settings.php(771): do_action()
#3 /mnt/web718/a2/30/510219830/htdocs/relaunch/wp-config.php(103): require_once('...')
#4 /mnt/web718/a2/30/510219830/htdocs/relaunch/wp-load.php(50): require_once('...')
#5 /mnt/web718/a2/30/510219830/htdocs/relaunch/wp-blog-header.php(13): require_once('...')
#6 /mnt/web718/a2/30/510219830/htdocs/relaunch/index.php(17): require('...')
#7 {main}
  thrown in /mnt/web718/a2/30/510219830/htdocs/relaunch/wp-includes/class-wp-hook.php on line 353