I'm trying to run a model that contains beam and solid elements.  I've greatly simplified what I'm actually analyzing to figure out why my contact sets between a beam and a solid are not working.

I have a large beam cylindrical beam standing vertically and is fixed on it's bottom joint.  I have a plate constrained to the cylindrical face of the beam via contact set (it's also constrained in the model).  It meshes completety fine.

When I click solve, I get an error that says:  "Model is unstable.  Check that you have applied adequate fixtures to stabilize the model"

I don't understand why.  The only part that has a fixture is the beam.  The plate is bonded to the beam and cantilevering out from the cylindrical face.  Why isn't the bonded contact set creating a "weld or adhesion" that makes the solid and beam move together?