I just installed my MK3 yesterday and followed the instruction to do auto level but always stopped on the hot bed, then showed error. It is not cheap to buy such function. I hope the manufacturer can help me to solve. On the other hand, the installation manual is very bad for deluxe model, no any instruction to install add-on components!!!
After searching and thinking, I concentrated on the mechanism of levelling by the probe and tried again.
I found the problem is the touch disc of the probe should be right below the nozzle.
Before, my probe is not completely force to fully extend the disc under the nozzle.
Now I got the answer and hope other people can use my solution.