The coffee beans may not be fresh.
Fresh coffee beans or freshly ground, high quality coffee are the most important ingredients in making a great tasting drink.
For a wide selection of coffee beans hand picked by De'longhi to help you get the best out of your machine please see the following link.
Raw Coffee Beans: our top picks at home | Coffee Lounge UK (delonghi.com)
Once your coffee is opened it will start to lose its freshness rapidly, we recommend it is stored in an airtight container.