I don't understand why it showed up with blue pt it not the pink?

Lupita • married an anime junkie like me. Love to watch 90`s sitcoms, and draw, paint, cosplay. my fav 50"s sitcom is i love lucy. my fav disney princess is jasmine. looking to make newfriends.
I took a blue ink pt and got a vvfl and also tweaked it myself and the line is there but when I took a pink ink pt nothing showed up. Why is this happening? And it was with fmu. Plz no rude comments. I don't know what to do. I'm 2 days late. Why was the blue one able to pick it up but the pink one wasn't?