Tips to solve our problem would be mutch appreciated. :-)

Machine type Mzak Super Quick Turn 250
control system Mazatrol 640T
Main A 365W000-B5
Main B 369W001-B5
Ladder 424W320-V201

Alarm comes after 2-3 Hours.
Alarm kode 225 : Front door sensor feilure (Sensor is relatively new)