Fixed atom in NPT run

Hi

I want to run MD NPT with forcite modules.In my system some atoms should be fixed and i fixed them in modify>constraints.

But i can not do dynamic simulation with this error:

Dynamics can't apply a barostat with fixed particles.

Removing all particle constraints may allow the barostat to be used.

would you help me what can i do to solve that?

Thank you

SJN