Steam wand leaking. Not enough pressure for a good shot!
I'm not able to fully close down the steam wand. So, when the machine builds pressure to steam milk - or to pull a shot - the steam wand leaks and releases pressure. My machine is only a couple of years old, but this problem has been getting worse to the point that it's nearly unusable. The espresso I can make with this problem ranges from so-so to undrinkable.