I have the same problem here.
First the light flashes blue once per second, then when I press reset it flashes rapidly yellow.
What I already did:
I cleaned and emptied the drawer
I removed all litter and replaced it with new one
I cleaned the circuit boards of the DFI sensor with isopropanol
I checked if the metal pins from the anti-pinch safety feature are touching each other and cleaned them with sandpaper and WD40 as suggested in another thread.
My SN is LR3CI134867 (date: 08.08.2020)
Any further suggestions? I need a fully working unit as I am about to go on a business trip.