I’ve run the calibrate height then auto-calibration a number of times and I’ve tried twice to print the keyring but it failed each time. I don’t know if this is a calibration problem. Sometimes in auto-calibration the nozzle goes down and it sounds as if it is thumping the bed rapidly a few times, then it carries on. Sometimes it finishes the calibration without any thumping at all. Each time it says Calibration OK, I save the settings and try to print.
I’ve tried tapping the bed at several points all round and near the middle, the red light flashes each time although when it was making the thumping noise I didn’t see the light flash.