Hey guys, i'm having trouble with the chin part.

-First of all i got my razor honned and i did 40 strop pass.
-I took an hot shower, and used Prorazo Pre-Shave.
-I lather my face with Prorazo white.
-I only use one technique up to down with little hit.

The problem is that my upper face is shaved fine but the chin and the jaw part is rough.
Is it my razor angle that is wrong or should i go against the hair?
Advice would be much aprecited, i really need to get better technique, thank you.