Autocad import for plane geometry

Dear,

I am having problems importing a autocad dxf file into Comsol. I am using Autocad 2019, but also saving into 2013 format does not seem te work. I also check if there were multiple layers, but everything is stored as one layer.

The error I get when importing it within plane geometry is: 'does not contained geometry objects'.

Figures were polyline > region, and everything looks ok. Is this a problem in Comsol or should I do something with the files before saving it as dxf?

best wishes,

Wouter