I think there is a bug in offline routing, when startPoint or endPoint (or both) is in white area (no street, road) it cant find path.
as you can see in screenshots attached, it coulld not find the path between startPoint and endPoint, even if a big city like Tehran (capital city of Iran) is between the start and end point!!! Although it happen in small distance too where one or both of start and end point are in white area ( no street, road, etc)
I have attached error too.
by the way it happend in GraphHopper Maps too. the screenshot is at the end.
thank you for your time.