Stopped working for no apparent reason.

Sometimes they have a external fuse which is close to where the wire goes in.

Or, the element has failed. Do you have a digital multimeter? Both items are easy to test.

Or it may have a thermal fuse, again an easy test with a meter.

https://www.google.com/search?q=DeLonghi+Alfredo+toaster+oven+XU21+ST+suddenly+stopped+working+after+baking

Videos. The make is not important as they all work the same and are all made by the same factory in China.
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Hola, lo m?s seguro fue que se da?? la resistencia (lo que haces que caliente) tendr?as que mandarlo a revisar con t?cnico

it is several prosibilites for your problem:
1) the wire of the oven is damaged;
2) the thermostat is decalibrated or damaged;
3) one or more heating element is intrerupted or burned.
solution's:
1) check the wire an replace or repair where is posible whit similar heat resistant wire;
2) replace the thermostat whit similar one;
3) replace the heating element

get your volt ohm meter out unplug it and disassemble it check your heating elements if there is no resistance the elements are bad. ONLY if you are comfortable with ac voltage!!! turn your meter to check ac voltage VERY CAREFULLY make sure nothing is shorted plug toaster in press toast button down. this should send voltage through thermostat to the coils . if you measure voltage across toaster switch when it is depressed the switch is bad. check your thermostat same for it if there is voltage across it it is open (bad).

Solution: buy a new toaster oven. I determined that the manufacturer stopped selling replacement heating elements in 2006, three years after the model year (2003). After market parts makers don't sell the elements for safety and liability reasons. So I got a new one.

Having a toaster oven and a coffee maker on the same circuit is asking the breaker to trip in the house electrical panel, but I guess that you have learned the drill: only one appliance on at a time. Try moving the oven to the working side of the socket (the two socket sections can be spit apart and power each half from a separate house breaker and wiring). If the oven now works, check for a tripped breaker in the house panel. If the oven still doesn't work, look for a reset button near the cord entry point. Many heating type appliances have a thermal fuse that opens when things get too hot, but you need to get inside the cover where the cord enters.

check the switch or thermal fuse, if it has.

Trace the electrical circuit with a multi-meter, while unplugged.

something had been gone short due to the power socket.let the socket be ok but sometimes due to heavy voltage this could possibly happen.just check if somme parts is burnt ,turned black or smelling foul oudor,or when you on the machine now it passes burning fumes from some where.

The contacts for these toasters fail. The plasic cam that depresses the contacts also can melt. The design is poor and no replacement parts are available. When selecting a setting, if the selection is not exactly perfect, the contacts arc and eventually fail. Unless cuisinart changes the selection cam to a solid state or relay, this failure will continue to happen during normal use. If your unit works properly do not switch the function setting while heating, this will cause the contacts to arc and erode the contact surface. This posting is applicable to the TOB-30BC, TOB-30BCC and probably all TOB-30XXX models.