If your air fryer isn't pre-heated your spring rolls need more time to cook. Another problem you could run into is if your spring rolls are too crowded in the basket. Make sure you give them space so that the air can circulate and heat them on all sides. Also, be sure to flip the spring rolls halfway through cooking time. All air fryers are different so the bake time will vary depending on your model. Refer to your owner's manual for the best estimate of time.