in the webassist/globals/global.php file, try changing:
$WAGLOBAL_Root_URL = ((isset($_SERVER['SERVER_PROTOCOL']) && strpos($_SERVER['SERVER_PROTOCOL'], 'HTTPS') !== false) ? 'https://' : 'http://') . $_SERVER['SERVER_NAME'] . ( (isset($_SERVER['SERVER_PORT'])&& $_SERVER['SERVER_PORT'] != 80)?":".$_SERVER['SERVER_PORT']:"") . $assumedRoot;
to:
$WAGLOBAL_Root_URL = 'https://' . $_SERVER['SERVER_NAME'] . $assumedRoot;