it was the snaps, I changed the osmode to 103 and it worked.
But it threw up another problem. the routing only works in square grids, i.e 2X2 , 3X3, 4X4 etc.
if you try 2X4 it doesn't work.
Someone in my work suggested it may be to do with integers and real numbers. but I don't know, I'm new to lisp and every function is a discovery to me.