The safety thermal-cut-out activated. The pump overheated.
Press the 1 CUP and STEAM buttons simultaneously for 5 seconds to ensure the machine is off. Unplug it from the wall outlet. Let it cool down for 30 to 60 minutes.
After it cools, plug it back in. Check that the water tank is full and properly seated. Press any button to turn it on.
IF THAT DIDN'T WORK: If the machine ceases operation again, the issue is persistent. Do not attempt further repairs yourself. Contact Breville Support or return the entire appliance to an authorised Breville Service Centre for examination.
HEADS UP: Always switch the machine off at the power outlet and unplug it if it will be left unattended, moved, cleaned, or assembled.