Probably one of the runes is misplaced. Did you build it by hand, or did you use the ritual diviner? If the latter, is there any chance that it wasn't able to place one of the runes due to a block being in the way?
I built it with a ritual diviner that can place dusk runes. When i right click it with the activation crystal it says "You feel a pull, but you are too weak to push any further."