I think it's very simple. In your new calculation, you use default runtime parameters, which means verbosity level is 0, i.e. ATK will not print anything to the screen.
So, I'm quite sure the calculations is actually just running!
However, there is a bigger problem: The default runtime parameter also means there is no new NetCDF file! So, once your calculation finishes, you will not have any NetCDF file with the final, converged result.
So, I would interrupt the calculation and make sure you also include runtime parameters by adding the following 3 lines before the executeSelfConsistentCalculation() statement:
import ATK
ATK.setCheckpointFilename('new_calculation.nc')
ATK.setVerbosityLevel(1)