more than one of the same product

Hi, I have one item that I sell, it weighs .6kg. If all the weights are set and there are rules set your plugin works well when one item is in the cart. When I add adjust the quantity to 2 or more of the same product, it give me an error for the shipping “There are no shipping methods available. Please check your address or contact us if you need any help.”

Is there a reason that this is happening?

thank you

https://wordpress.org/plugins/weight-based-shipping-for-woocommerce/