This is normally caused by water spilling or leaking into the base of the appliance, activating the anti flood device.
Unplug the appliance.
Take it out and take the side panels off.
Remove any water in the base of the machine.
Once removed, plug in and run the machine.
while it's running, watch to see if it's leaking.
If no leak, you can reassemble and put it back in place.
If it's leaking you need to locate and cure the leak to rectify the problem.
If there's no water in the base, check to see if the microswitch on the left side (look for the red rod) has stuck.
Check it out, see what you find and get back to me.
Hope this helps