When I try to drag all of the answer buttons to the AnswerButtons array in the Unity UI, I get a “not allowed” icon on my cursor. I had to click a + button to add four entries to the array and then assign each one to a button. My version of Unity is newer than the one in the video (6000.2.15f1 vs 2021.7.1f1 in the video). Has this functionality changed?
Hi deus777,
Welcome to our community! 
Unfortunately, without knowing anything about what you did and see in Unity, it is difficult to help you with this problem. Maybe the type of the button array is wrong in your code?