Hello Jim,
I am also getting this same error message. As well as several others. This is on my new K1 Max. Yes, this error message showed up right after I updated the firmware to 1.3.2.20 from whatever was on the machine when I got it a week ago.
I suspect there is an actual hardware problem and here is why.
With the original firmware the printer has only managed to successfully print one item. The pre sliced test cube. That item did not have a perfect first layer but it worked. I had enabled all the Camera AI functions for that print. Everything else I have attempted to print since then has failed. The first layer is just not level to the build plate.
I attempted to run the Auto Leveling Self Check a few times and it was digging deep scratches into my build plate. Lucky for me I flipped it upside down so only the paint was scratched.
I followed the steps to Manually level or Tram the Build plate. Opened the bottom of the printer took off the belt. Bolted the Z mounts to the bottom of the printer. Put the belts back etc. But it would still dig into and scratch the build plate after that.
Then I attempted to upgrade the firmware to 1.3.2.20. Now, it fails to even start the Auto Level Self Check. Instead, it gives me one of the error Key:2521 messages.
I rolled back to Firmware version 1.3.2.1. The error messages stopped but I still couldn’t get the machine to pass an Auto Level Self Check. It would keep digging and scratching into the build plate. That is not good. Then I upgraded to 1.3.2.20 again and am back to where I started.
I did go into settings used a factory Reset with all the boxes unchecked. That didn’t do anything to fix the problem.
Here is what I can do to repeat the different errors I am getting. Again, this is a K1 MAX running 1.3.2.20 firmware.
I power off the printer. Wait 10 seconds then power it back on.
Using the touch screen I Click into movement and click to Home Z
The Machine will home X and Y first. Then it will lower the Z by about 5 mm and nine times out of 10 it will give me this error message. “Error key:25``,Leveling Sensor Chip Anomaly or Sensor Damage.”
On the rare occasion that it doesn’t give me that error message right then it will wiggle the build plate up and down and bit then move up toward the nozzle. (It gives me hope.) Once it comes into contact with the nozzle it lowers by 5 mm and then gives me the other error messages. “Error Key:2522, Level Sensor Data Transmission Anomaly.”
If I attempt to run the Self Check it will give me one of the two errors as well.