You need to do two things so the coffee dregs ( remainings) become more dry.
The first thing is clean coffee group injection valve which in
parts diagram are the parts no 44, 52 70, 14, 23, 41, 47, 55 page 2/4. All these parts are full of dry coffee and can be clean with warm water.
After the cleaning try the machine and if the espresso flows slowly then adjust the coffe grinder one step to more cross coffee. You can find all other informations documents, instructions and parts to this
link