The worlds do not appear even though they are in the "minecraftWorlds" folder and when creating a new world it appears "There was an error loading this world" 

And then the world appears in the list of worlds and says that it weighs 131051, 8 GB.

And when trying to open the world, another message appears saying "There was a problem loading this world"

And then the world just disappears

I want to highlight that the servers do work correctly.