Ciao :D
Thank you so much for your help and especially for your time in solving this problem! I followed your advices and now the simulation seems to get better although there are still some problems. I do not want to waste your time but I would be delighted to have a talk with you!
Dear I did not change anything between the two analysis. I took the converged analysis, cleared the generated data and ran it again.
I thank both of you for your support.

Regards Daniele