We are attempting to perform a crane lift of a very large tank and I am getting a negative ten million stress but only when I apply cyclic symmetry. I have done smaller tanks with this exact same method without any problems but now I have problems. I have the pick-points fixed with just gravity as the forces to simulate the tank hanging in the air. The pick-points on the bottom would be connected by cables on the inside of the tank but since this is not working, I have not bothered to model yet.

Does anyone know how to fix this? I have attached the model