engine paint

i just got back from laying the first layer of paint on my oilpan and i just dont get why i got a few very small spots that the paint just refuses to stick to,its on the bottom of the pan so i realy dont care for the visual aspect of it but its kind of disturbing.
i did a good cleanup of the pan,sanded it properly and cleaned it with the right solvent to make sure it was clean and dry and it just refuses to stick to those spots](*,)



any sugestions?