Based on this, a leak into the base is the most likely reason.
https://www.justanswer.com/uk-appliance/7fiza-smeg-dishwasher-error-code-e1-clear.html
HOWEVER, it might just be that the float switch is now stuck in the "flood" position. You might be able to gain access somehow and check it has reset itself correctly.
Emrfjj, May 2024
