Not Enough Boundary Conditions

I am trying to simulate the deformation of the(copper)ring when a tensile stress is applied to the OD ofthenon-slotted area. Apply only the normal stresses andnorestraints will give me a  message of "Not EnoughBoundaryConditions" when I execute the analysis. I do notwant to (fix)restrain any of the surfaces because it wouldcompromise the result.

Does anybody know how to apply the appropriate stresses/boundarycondition to simulate this scenario ?
Thanks in advance !SolidworksSimulation