It won't let me replace a real world with another world

Put the summary of the bug you're having here
It won't let me replace a realms world with another world

What I expected to happen was...:
Describe what you thought should happen here
That the world will be replaced

What actually happened was...:
Describe what happened here
I get an error and it won't let me copy the world

Steps to Reproduce:
1. Put a step by step guide on how to trigger the bug here
I put myself to the realms to a world I try to replace it with another and I get an error and the world is not replaced