There is no evidence that du`a made when seeing the Ka’bah is answered
Question

Someone said that supplication made at the first sighting of the Kaaba is always granted. Is there any truth to this?
Praise be to Allah.This is not true; there has to be evidence (daleel) for this to be true, because acts of worship should only be based on evidence. And that evidence must be saheeh in and of itself and it should be clear and unambiguous. And Allah knows best.