One reason why a piece of toast does not pop up from a toaster is due to an incorrect thermostat setting. To solve this problem, the thermostat inside the toaster must be reset by turning off the toaster and opening it to reach the thermostat controls.
In most toasters, the thermostat is controlled by a knob, nut or screw located inside the front cover. This switch is typically located by the light-to-dark toasting control that is found on the outside. This knob, screw or switch must be turned towards the left towards where the toasting control function indicates a light toast.