I need some advice about having neighbours with kids.

So my neighbours kids came over and asked my 4 year old daughter to come over and play. Which she has on many occasions I said that’s alright you can go. They have played a couple times at my home also. My sis in law was there and she said why don’t you come play here. The girl then said oh no my dad said I’m not allowed to play here anymore.. only that my daughter can come and play there. I’m not sure what to make of that.