Monopole Antenna : error doing lambda refinement

Hy,
I am a beginner in antenna propagation and HFSS. I have a quesion about the monopole antenna.
I fixed my antenna on a cylindrical Cavity build with a NEW material with relative permeabilty 1000.
when I valdiate it does not display errors and when I click on analysis at the beginning it works then it stops doing in lambda refinement as shown in Figure

thanks in advance