SWITCH OFF YOUR MACHINE
Once the Machine has completed its cycle

Remove, empty and clean the Dreg Drawer.
{This usually is the cause, remember to reset your 'Bean' quantity}

Remove the Brewing Unit 
Push and hold down the RELEASE tab, slide the unit outwards using handle.
DO NOT USE EXCESSIVE FORCE

Check for any obvious damage and ascertain that the unit is solid and that moving parts are firm when you try to move them.
The brewing unit should be well cleaned (NO DETERGENTS).
Ensure the 'hopper' (where the freshly ground coffee drops into) is clean and that there is no 'caked-on' coffee.
Check that the 'plunger' is clean and that the 'O-ring' is not broken or out of alloignment..
Check that the 'Wire' scraper is firmly in place and not damaged.
Vacuum/wipe out the brewing compartment.
Replace the BREWING Unit first.
JUST SLIDE INWARDS WITHOUT PRESSING DOWN ON THE RELEASE.
You should hear a 'click' when it is locked in place.
Replace 'Dreg Drawer' and close door.

SWITCH ON YOUR MACHINE

Set your 'BEAN' quantity to 1 and make a single coffee.
Ensure the grinder is not set so as to grind the coffee beans too finely.
If all goes well then try again at 3.
You should finish up with a setting of 4 (SOMETIMES 3) depending on the fine/coarse setting of your grinder

CAUTION:
When using 'pre-ground' coffee be sure you are not placing excessive coffee down the shute.
The 'BEAN' quantity is bypassed when doing this.
Be sure to press the correct icon for making coffee in this manner.
Never add anything other than coffee to the shute.
DO NOT USE VERY FINE COFFEE SUCH AS Turkish/Greek Coffee
All powdery additions will block your filters and damage the machine.