Saeco Incanto Classic

I have a Saeco Incanto Rapid Steam Espresso Machine, my machine is always on, but lately when I make a cupacinno, the machine turns off and without me turning it on, it will restart by it itself after fifteen minutes. Could you please tell me what the problem might be. I would appreciate the help. Every time I ask for help, you've always fix the problem. Thank Lina Cornacchia