Exoskelton (ExoW) error

Hello, now I have Exoskelton (ExoW) error,
“1. One or more struts is engulfed by its nodes”

Could you help me?

I’d like to make my model to “Exo skeltal body”.
↓ I want to make my model like this.

model.3dm (4.7 MB)

problem.gh (10.1 KB)