I have taken a look at the mesh error. It seems that the Issue is actually with the CAD.
The CAD has No Solids or Shells but only faces ( probably an open shell ). This can be problematic for the meshing.
Please edit you CAD model in any CAD software to make sure it is a Solid or a closed Shell. It is recommended that the CAD is ideally 1 Solid and imported in STEP format. It should then work with the meshing.
Also just a heads up. After importing make sure the geometry has the right scale. As SimScale works in SI units of Meters, make sure the units are correct.
If you still have problems, feel free to let us know.