Machine powers on but does not start brewing when a coffee button is pressed.

Safety first: Unplug the machine before manipulating internal switches.

Step-by-step:

• 1. Check all containers: Remove and firmly reinsert the drip tray, coffee grounds container, and water tank. Ensure they are fully seated.
• 2. Verify brew unit: Remove the brew unit, rinse it, and reinstall until it clicks into place. Close the service door completely.
• 3. Inspect door switch: Gently press on the service door while trying to start a coffee. If it starts only when pressed, the door switch or latch may be misaligned.
• 4. Check display messages: Look for icons or text indicating which component is missing or not recognized.
• 5. Professional service: If all parts are correctly installed and the machine still will not start, a faulty microswitch or sensor may need replacement by Siemens.