Verify that the item you have in your barn or silo is exactly the same needed for the delivery or the production. Some icons in the game may look similar (for example, the berries’ icons), and some times it may also happen that you need a particular version of a product for the delivery (for example, you may have tomatoes but the delivery requires roasted tomatoes, or you may have cherries but in order to produce a popsicle you need cherry juice).