Strangely, my Group Finder Tool does not allow me to queue for Flashpoints. I can queue for planetary destinations, but all my Flashpoint options are greyed out despite being lvl 19. I was able to group up for Black Talon once, and nothing after. I've asked around and no one else seems to have this problem. It's very strange.
I had to go and pick up the quests for the Flashpoints first then log out and back in to queue for flashpoints.