Using a Frictionless Support on the top face of the concrete block is a mistake, delete that.  Insert a Frictional Contact between the top face of the concrete block and the bottom face of the flange (unless you already have this in your Connections folder).

Please show the items in your connections folder. Do you use Bonded or Frictional contact of the head to the flange?  Is the bonded contact between the hole and the new lower part of the shank?  Sometimes previously defined contacts only appear on one of the two faces when that face was split into two pieces, and it is sometimes not on the face you want.

Bolt pretension can only be applied to cylindrical faces. Where did the geometry come from?  Check that the face is actually a cylinder.