Instantiate a canvas with a button when trigger

I'd like to Instantiate a canvas with a button when player enter a trigger. And the button could set other exist obj inactivity.

I save the canvas as a prefab and it has the function to set obj inactivity. Then I write this code:

 > void OnTriggerEnter(Collider other){
 >         if (other.tag == "Player") {
 >             Instantiate(CanvasBtn);         }

It could create the button but its onclock function does not work. Could someone explain it to me? Thank you.