Naturtint Fireland (I-6.66)

Comment: My natural hair color is black. I had it previously dyed with henna one time. The henna did not work at all, therefore, my haircolor did not change. I had 1 inch of black roots and the rest was a dark red. So, today I dyed my hair with Naturtint fireland. Surprisingly, it did not dye my black roots at all! My roots were supposed to be red. It only worked on the rest of my hair. Here is what i think might have gone wrong:

1. The previously dyed henna affected the results. Even though the henna
did not work on my hair.

2. I started to dye my hair at the nape of the neck rather than at the
front. It took me 1hour to dye my own hair.

3. Or maybe the product was defective

Why cant i just dye my hair red and have it turn out red?

Everyone else gets to dye their hair and be happy with the results! Why me??
Nothing seems to work on my hair, not Henna, and maybe not Naturtint. I will dye it again and see if it works this time.