With the mains disconnected, remove the lid and invert it and place on jug as shown. (This keeps the lid upright and steady)

Note that there are 4 pins on the lid section and 4 holes in the jug section (yellow arrows)

Spray some electrical contact cleaner on the 4 pins and replace the lid section the right way up on the jug about 20 times, so that that the electrical contacts rub against each other numerous times to remove any non-conducting residue.

Wipe away any liquid and allow to dry (for an hour or so?)

Hopefully the soup maker will now come on when plugged into the mains. The buzzer should sound and the LED lights should flash awaiting the mode button to be pressed.

If the soup maker does not turn on, disconnect from mains and repeat the cleaning process with the contact cleaner.