Can't join custom world

[BreadToaster343]

My friends and I made a world that was western theme and was separate from the over world and the end and nether. 

It worked fine last time we played, which was yesterday, and tried to get back on today but the /worlds or /world ul_[insert worlds name here] didn't work and any attempt to get back to it wasn't working. I even went into the files and the world file was still there but wasn't showing as one we could enter into in-game.

Does anyone know why this is and how to fix it? the version is 1.16.5

EDIT: Thanks, but how do I add a new world to make it work with the Multiverse plugin?

Edited August 4, 2021 by BreadToaster343
questioned answered but new problem of how plugin works

[rabszabs]

im having the same problem. someone said that they removed the command /world. i tried to use the multiverse plugin but it didn't work too

[_Tarna_]

PlayerServer was removed, the plugin that gives the /world and /worlds plugin so you can't use it anymore. You would need to use a plugin like Multiverse to teleport between worlds.