I know this is an old thread, but I just wanted to add, I had this exact same problem for a couple of days and I tried everything, I've just figured it out. Where the sensor is, where the plastic slots into the gap at the front of the printer, there ...
Did you ever get this fixed?? I'm having the exact same problem now. Managed to get it to work last night after unplugging, but now we're back to square one.
