Water balloon deformation

Hello,
I've only recently started using this program, so my level of knowledge is not very high.

I'm trying to model the physical deformation of a water balloon due to external force (get the shape in different time steps).
I've tried using the fsi physics module, defining a liquid domain surrounded by an elliptic elastic solid body domain, kind of like an ellipse within a ring.
I then applied different boundary loads on the outer boundary of the solid domain.

When I try and run the simulation I get an error stating that there are no consistent initial values. Why does this happen? Is there a fundamental piece of information i'm missing?

Thanks,
Raviv