embedded constraint 1

[carolina000]

hi ppl!

I've created a tiny volume and the area around it by cutting a cube around the volume. I defined sets before meshing and there was no problem with meshing both.
When I add the constraint that the volume is embedded in the host, I get error messages "1532 nodes on an embedded element do not lie in any host element. Check coordinates, exterior tolerance and absolute exterior tolerance parameters, and the host element set definition." I have changed both tolerance and fraction tolerance and am going nowhere...
If I don't define the constraint there are no errors.

Have you ever encountered this before?

Thanks in advance!
Carolina