The pressure left the group!

Check the top of the group, you will find a nut which is about 19mm, within that nut is a micro-screen, and a small jet. Make sure the machine is cool and the inline water is turned off. The jet maybe clogged, get a paperclip or some pipe cleaners and clear, check screen for buildup, there might also be a small amount of sand in there(Minerals from the water), easiest way to clear it slowly open the inline water. BEFORE REMOVING THE NUT CHECK TO SEE IF THE GASKET UNDER IT IS TEFLON OR SILICONE. IF TEFLON GO AHEAD, IF NOT MAKE SURE YOU HAVE ANOTHER ONE ON HAND BEFORE YOU PROCEED.