Echo's mesh is unbindable with Groom in 5.6?

Any idea why Groom no longer binds to Echo Windwalker in 5.6?
Echo’s mesh seems to be outdated.
Everything seems to indicate the mesh itself is not bindable. While for example Manny is. Tried different grooms, bindings, etc. And because groom is now more strict it seems unusuable without a proper binding.
Is there a way to fix it?

Seems like a good opportunity to understand the system better.