I believe if you change the line max_steps that will fix your problem. Currently you have the max iterations at 100 and usually when i exceed the 100 steps for my systems, I have set up my geometry incorrectly.
the line is under iteration control parameters in the vnl
and it look like this in your script.py file
iteration_control_parameters = iterationControlParameters(
tolerance = 1e-005,
criterion = IterationControl.TotalEnergy,
max_steps = 100
)