Is "Set Material " broken in ver. 4.16? "SOLVED"

Hi, I’ve been trying to create a very simple blueprint, where a button on screen changes the texture of an object in the scene, and its a typical setup where the UMG is loaded from level blueprint, then object is changed into a blueprint, and in the umg the button first gets all actor of the class and the “for each loop” passes the blueprint of the object to change its material. this setup works in my old version 4.11 but somehow I cannot link the “array element” from “for each loop” to the “target” in “set material” in 4.16. you can see the setup working in 4.11 in the screenshot. but i cannot make the last connection in 4.16.
Edit : So I tried creating a new project in 4.16 and it works there so the problem is in my current project setting.
Edit2: it looks like the problem was with the button, someone deleting it and creating a new one solved the problem. Cheers