Looks like ms.php
file is not loaded for cron job.
Try to add following line at the beginning of your plugin:
require_once ABSPATH . 'wp-admin/includes/ms.php';
Looks like ms.php
file is not loaded for cron job.
Try to add following line at the beginning of your plugin:
require_once ABSPATH . 'wp-admin/includes/ms.php';