I have a problem with my Jura impressa x7 coffee machine. When it is turned on, a message saying 'missing drip tray' or 'please insert drip tray' appears. when in fact the drip tray is already inserted. I'm assuming it has something to do with the sensor at the rear of the drop tray but I am not sure if it can be repaired or just needs replacing. Please help!

SD, August 2012