Facetime not working on old phone without sim

I replaced my old iphone 5 with a new iphone. I want my son to start using the old iphone for facetiming with his grandparents, using wifi. As my old iphone 5 does not have a sim anymore.

I am trying to use a new appple id for this facetime. But its not working.. when i try to set it up with the new id and password, it says the connection type is not correct or not available,.

please help