Baked Lightmap Issues - Some objects completely black

So I recently modelled a small bedroom scene so I could test out baked lighting in unity.
And after some fiddling the best I could manage was this:

A few objects like the walls, the posters on the wall, and even a small part of the Switch on the table are receiving light.

But others such as the bed and table are completely black. I thought perhaps the reason could be because I’m using an inverted hull outline, but if that were the case the Switch on the table wouldn’t be receiving light - but there is a small portion of it that does.

I’ve made sure to make Lightmap UVs and have even checked them, and they look fine. But most of the lightmaps themselves are completely black. Does anyone have an explanation for this?

Are these GameObject is checked as static and in import setting of the model, generate lighmap uvs is checked too?