Looks like a beaded joint to me, which uses the opposite of the convex jointer you attached, actually requires a concave jointer, probably about 3/8" or smaller. Just a note to the OP, these joints are extremely difficult to make, especially for a newby......Yes there is a special tool. Brick jointing tool.
There are different sizes and shapes, so first examine the size and shape of what is on the rest of your house. Commonly convex, but might be flat also.
Also looks like you put too much mortar.