Aquí estoy usando socket.io-redis cuando llamo al método provider_join rooms = io.of("/").sockets.get(providername); la sala está recibiendo TYPEERROR, por favor ayúdenme gracias de antemano

 const express = require('express') const app = express() const server = require('http').createServer(app) const io = require('socket.io')(server) const redisAdapter = require('socket.io-redis'); io.adapter(redisAdapter({ host: 'localhost', port: 8000 })); io.of('/').adapter.on('error', function(){}); var room; io.on('connection', (socket) => { socket.on('provider_join' , (providername) => { rooms = io.of("/").sockets.get(providername); if(room == undefined){ socket.join(providername) room = io.of("/").sockets.get(providername); socket.emit('room_created', providername); }else { socket.emit('room_already_created', providername); } })