Problem with stability of contact in LS-DYNA

Hi,

I have a problem in LS-Dyna with stability of the contact between rigid bodies and solid body, where penetration is appearing and simulation is failling in most of cases. I have simulation of tube rolling, where 3 rollers expand tube to fit in the metal sheet. I started to use mortar type of automatic surface-surface contact, but it did not help. I am using rigidwalls to fix plate in place, but I noticed that LS-Dyna displays also error with initial penetration of them.