If you are following my recipe and your sweet potato fries aren't crispy after being cooled for a few minutes, then most likely there were too many in your air fryer basket. Overcrowding leads to steaming and they won't crisp up. It is important that you air fry them in a single layer or as close to a single layer as you can get. I found that one large sweet potato cooked in two batches in my air fryer worked great.