CoolZonee

You need to have a Plugin called "Multiverse-Core" I believe, After you have the plugin restart your server than upload the world in your file-manager, Just go to Filemanager > And upload your world there, After you did that Execute the command /mvimport <world name> normal/nether/end Ex: /mvimport example normal You also need to give yourself op from the console first to execute this command. There might be other ways but this is the way i have been using

What client are you guys on? This could be a client problem, Although I am having the same issue