I have seen many posts about this sort of problem. However, having used a flexible curtain wire to investigate the drain hole where the defrost water in the fridge should go, I found that there was no upper blockage but the wire would not go any further than 17 inches.Something hard was stopping it. The back of the appliance is more or less totally covered at the back but I’m assuming that what I can see is a drain pan sitting on top of the compressor as there is an inch of white tubing coming down into it. When I put he curtain wire up this tube it would only go a little way before it met with the same kind of resistance as when I inserted it from the fridge.The drain pan was completely dry.
I have only had this appliance since the end of March so I’m completely baffled as to what the problem is.