The coffee is ground too coarsely.
- Turn the grinding adjustment dial one click anticlockwise while the coffee mill is operating.
- Deliver two coffees. The adjustment only becomes visible after two cycles.
- If still unsatisfactory, repeat: one more click anticlockwise, then two more coffees.
Alternative cause: The coffee beans themselves may be unsuitable. As a test, use pre-ground coffee for espresso makers in the pre-ground coffee funnel.
Prevention: Major adjustments should be done one click at a time, with a two-coffee test between each.