When I tried to create a copy of my world it would just say "Failed to create copy of world."

Whenever I tried to create a copy of my world with the Copy World button in the world menu, it wouldn’t work and just say "Failed to create copy of world." I have tried multiple things to fix this, even copying the world file manually. It made the copy but I could still not create copies with the button. I don’t know if it was something I had done in my world or what.