Hi all, same thing happened today wir my 2.0 Nuki FW 3.10.7
Mathias’s Solution with resetting helped. But it wasn’t really not obvious, ‘cause in the process you’re guided through Calibration, which states clearly, that you should make sure that the door is unlocked.
Small guide, or actions which helped:
Nuki>
Settings>
Features & Configuration >
General
\Scroll all the way to the bottom// >
Reset Smart Lock>
Restore Default Settings>
Restore now>
\Here it takes some time and asks if you want to calibrate, and “Make sure the door is unlocked”//>
Calibrate
\Here it takes some time again and it seems like nothing happens, BUT you’re going to hear a small click of the latch, directly after that turn your key from outside
Hope that it helps others next time