It has happened to me and I went to several forums to try to fix it and it just wouldn't work. In despair I just used CLR, or a generic Calcium Lime and Rust cleaning spray directly on metal filter container and VOILA worked like a charm. I just sprayed the metal cup and inside the portafilter, let it sit for some 10 mins then rinse very very well. Unbeknownst to be, I have hard water and the little holes where coffee was supposed to go thru were clogged.