ディスコードbotコマンド反応しない

import discord
from discord.ext import commands
import asyncio
import os
import subprocess
import ffmpeg
from voice_generator import creat_WAV

client = commands.Bot(command_prefix='.')
voice_client = None


@client.event
async def on_ready():
    print('Logged in as')
    print(client.user.name)
    print(client.user.id)
    print('------')


@client.command()
async def join(ctx):
    print('#join')
    print('#voicechannelを取得')
    vc = ctx.author.voice.channel
    print('#voicechannelに接続')
    await vc.connect()

@client.command()
async def bye(ctx):
    print('#bye')
    print('#切断')
    await ctx.voice_client.disconnect()

@client.command()
async def register(ctx, arg1, arg2):
    with open('C:/open_jtalk/bin/dic.txt', mode='a') as f:
        f.write('\n'+ arg1 + ',' + arg2)
        print('dic.txtに書き込み：''\n'+ arg1 + ',' + arg2)
    await ctx.send('`' + arg1+'` を `'+arg2+'` として登録しました')

@client.event
async def on_voice_state_update(member, before, after):
    server_id_test = "サーバーID"
    text_id_test = "チャンネルID"

    if member.guild.id == server_id_test:   # サーバーid
        text_ch = client.get_channel(text_id_test)   # 通知させたいTEXTチャンネルid
        if before.channel is None:
            msg = f'【VC参加ログ】{member.name} が {after.channel.name} に参加しました。'
            await text_ch.send(msg)

@client.event
async def on_message(message):
    print('---on_message_start---')
    msgclient = message.guild.voice_client
    print(msgclient)
    if message.content.startswith('.'):
        pass

    else:
        if message.guild.voice_client:
            print('#message.content:'+ message.content)
            creat_WAV(message.content)
            source = discord.FFmpegPCMAudio("output.wav")
            message.guild.voice_client.play(source)
        else:
            pass
    await client.process_commands(message)
    print('---on_message_end---')


client.run("botのトークン")
```
```### 前提・実現したいこと

https://qiita.com/Nemy/items/d895114d3ba9a9d7cb62
上記のサイトを参考にディスコードでテキスト読み上げbotを作成しています。

### 発生している問題・エラーメッセージ

.joinと打ったらボイスチャンネルに入出するはずなのですが反応しません。


エラー
None
#join
#voicechannelを取得
#voicechannelに接続
---on_message_end---
Ignoring exception in command join:
Traceback (most recent call last):
  File "C:\Users\user\AppData\Local\Programs\Python\Python39\lib\site-packages\discord\ext\commands\core.py", line 85, i
n wrapped
    ret = await coro(*args, **kwargs)
  File "C:\open_jtalk\bin\read_bot.py", line 27, in join
    await vc.connect()
  File "C:\Users\user\AppData\Local\Programs\Python\Python39\lib\site-packages\discord\abc.py", line 1277, in connect
    voice = cls(client, self)
  File "C:\Users\user\AppData\Local\Programs\Python\Python39\lib\site-packages\discord\voice_client.py", line 199, in __
init__
    raise RuntimeError("PyNaCl library needed in order to use voice")
RuntimeError: PyNaCl library needed in order to use voice

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "C:\Users\user\AppData\Local\Programs\Python\Python39\lib\site-packages\discord\ext\commands\bot.py", line 939, i
n invoke
    await ctx.command.invoke(ctx)
  File "C:\Users\user\AppData\Local\Programs\Python\Python39\lib\site-packages\discord\ext\commands\core.py", line 863,
in invoke
    await injected(*ctx.args, **ctx.kwargs)
  File "C:\Users\user\AppData\Local\Programs\Python\Python39\lib\site-packages\discord\ext\commands\core.py", line 94, i
n wrapped
    raise CommandInvokeError(exc) from exc
discord.ext.commands.errors.CommandInvokeError: Command raised an exception: RuntimeError: PyNaCl library needed in orde
r to use voice
### 試したこと

権限の確認、botの再起動、再招待

### 補足情報（FW/ツールのバージョンなど）

環境はWindows10、python3.7.9
上記のサイト通りに作成したのですがうまくいかなく困っています。どうぞよろしくお願い致します。