Your home and away jersey can not have the same primary color.

A "black and yellow" and a "black and orange" jersey combination will not work since the primary color of both jerseys are black.

A "green and white" and a "white and green" jersey will work since the primary colors are different. One is green and the other is white.

Unfortunately, you might have to play a game with a brand new premium jersey to figure out which color is the primary color.