I completely change my UI, and I have now a little problem.
I use ArcHUD to see my character, my pet, and my enemy. But now, I don't see my group characters anymore. I have to use "F2", "F3" ... to see them, but I can't see them everytime. Raid UI is working
It's ag_UnitFrames that controls your party frames. Go into the config/options and make sure your party frames are active and that they are positioned where you can see them. The HUD you are using should not effect the visibility of the party frames, just the player (sometimes pet, depending on the HUD), and the Target.