I had the same problem. Thought it was the pump so replaced it. Nope. I now have a spare pump if that ever goes.
The problem is in the portafiler (where you put the coffee). The inside gets clogged if you don’t tip it upside down and run water through the 2 holes in the bottom after each use.
You have to be really careful as there are tiny springs in it, but loosen screws, open up and clean. Maybe take a picture of it after openning and before touching anything.