Can't export blender project to WMO

[Helias]

I am using Blender 2.79 and I am trying to export a blender project to WMO format, I did not succeed for the following error.
Is there a way to fix this error?

[skarndev]

Do you have any geometry on your scene?

[Helias]

What do you mean? I am not so cool with Blender and 3D editing 😅
I have this

[Helias]

I get the same error with the standard Blender cube, so I don't think it's related to my project

[skarndev]

You did not set any settings for WMO groups in the add-on.