I own a Gaggia classic which I've been using for several years and which has always worked well. For a few weeks now, I've been unable to make a coffee, the coffee flows normally then quickly becomes transparent, as if the water were flowing directly.
I've always used commercially ground coffee (illy, lavazza), so I haven't changed a thing.
I have the impression from my research that it's "channeling", everything flows through a "tunnel" and the water doesn't go through the whole coffee.
I've dismantled the filter holder to understand how it works, there's a sort of spring that "closes" the filter holder, I don't know if the problem could come from there.
I'd like to understand the problem before buying either a new filter holder or a new machine
Here's a video of my coffee process that might help you:
Thanks for your help