I am trying to calibrate for the first time, and I am getting unreadable characters returned from the Serial Monitor. I've read a similar post, but my settings appear to be correct. I'm guessing I missed something in the docs:
Wait! It's working now - I think the Baud rate/newline setting was wrong.
I reset to No line ending and 57600 and it's working!
Yes, you need to make the baud rate match the serial setting in the code.