An order of any kind, including a stop-loss order, is only triggered when price reaches the order price level. If prices for the instrument in question are not being generated, the order cannot be triggered. When the prices start being generated again, typically when that particular market re-opens, then the order becomes active and can be triggered.
If price re-opens beyond your order, i.e., it gaps, the order will normally be executed at the first available opportunity after the open, whatever that price might be.