Why the campsite visitors refusing to move in my island in animal crossing?

So there this campsite visitors name Bud and I want him move in my island but my island is full

So I go to YouTube some say (the one without the amiibo) just keep talking to them and they will call the residents service and even maybe play a game

So I did that but after Bud called the residents service and they say no because my island is full. Bud didn't ask to kick somebody out. He just accepted it and refused to badge. I did play the game but it was just wining items not moving in

I keep talking to him to but he saying the "You didn't tell the island is popular" or something like that and call him if any plot is available

I just give up so why this is happening??


If you questioning why I post it here? It because almost all the subreddit of animal crossing in reddit doesn't approve this type of question?? Confusing I know! So I'm desperate for this answer