possess when initiating from a cast

So I am trying to possess a vehicle from a hud which is activated by a collision box near the vehicle, but it seems when I cast and call function from the hud it wont work, but the function works fine when called from event graph, I tried the 2 different variations and it wont work. Is there some setting to acknowledge mouse click maybe, because i tried putting a print text on cast failed and it isnt failing and a remove all widgets at the end clears hud so im confused!! any suggestions appreciated