If your Bellezza Bellona overheats, it will trip the safety themostats.
There are 2 thermostats, 1 on the coffee boiler and 1 on the steam boiler. You can see in the pictures below with a red circle. To reset them simply push the button on them. If they are hard to reach, you can use a screwdriver (as pictured) or even a pen.

Coffee Boiler

Steam Boiler
If the problem persists, you will have to take it to a repair facility to troubleshoot the issue.
