Defy 8Kg Dryer just beeps when I press start?

Hi guys.

Can someone help? I have a Defy 8Kg Tumble Dryer (Dfy 8504). When I want to start a cycle, it just beeps twice. Then nothing happens.
There is no other warning, flashing light or message. Any idea what is wrong and how I can fix it?

Ps: I have cleaned the filters and emptied the water tank.