Well, there are a few possible reasons. It could be because you didn't cook it long enough — samosas should be cooked until they reach a golden-brown color. It could also be because the samosa was made with stale ingredients — old potatoes and flour can lead to a soggy samosa. Make sure you cook it longer, use enough oil, and make sure the ingredients are fresh. Then you'll be sure to get that perfect crispy samosa you're after.