Hello good night

With friends, we had opened a realm on a server (Café Club MED), however the owner of the Realm could no longer pay it and no longer had the identifiers so that someone else could pay it, I decided to open my realm and assign the map there, unfortunately, after downloading the MAP from the former owner, I find myself in a dilemma:

When I replace the world to add the old MAP, I end up with an infinite loading that says to me: Error - An error has occurred.

Maybe the current map is too big and therefore cannot be replaced, but therefore the error should be known?

I pay for a service to be able to play the game where it's easier to play, I trust the services offered, please find a solution for me, it's a realm that we all particularly care about, because it's a way to meet up with friends despite the distance.