Discord,py 命令在 cogs 中以前有效，但在使用时找不到

Question

I haven't changed the code in my discord bot that runs discord.py in a while. It worked beforehand, but after half a year it stopped suddenly working as in the code somehow broke without any action. The bot runs and even is capable of using commands that are implemented in the main.py file. However, when trying to run commands that are written in cogs eg help.py it just gives me the following error:

    2022-09-27 14:58:00 ERROR    discord.ext.commands.bot Ignoring exception in command None
    discord.ext.commands.errors.CommandNotFound: Command "help" is not found

this is my code in main.py

#Library of imports
#---------------------------------------------------#
#Basic DC stuff
import discord
from discord.ext import commands, tasks
from discord.utils import find
#On message
from discord import Message
#OS
from dotenv import load_dotenv
from os import getenv
import os
#Status etc.
import math
import random
from random import choice
#Date & Time
import datetime
import time
#Misc
import functools
import itertools
import asyncio
from async_timeout import timeout
#Uptime
from keepalive import keepalive
#My imports
import settings
from settings import DISCORD_TOKEN

#---------------------------------------------------#
#intents = discord.Intents.all() #stopped for the moment, doesn't work - working version implemented in line 44 "intents=discord.Intents()"
intents = discord.Intents.default()
intents.members = True
intents.message_content = True
#-------------------Loads---------------------------#
load_dotenv()
status = [
    "sheep noises", "Fujara", "Life", "Horse nagging", "Sheep bliating",
    "Sheep™", "Sheep Simulator"
]

bot = commands.Bot(command_prefix='$',
                   case_insensitive=True,
                   help_command=None,
                   intents=intents)

initial_extensions = [
    'embed',
    'ent',
    'help',
    'music',
]

if __name__ == "__main__":
    for extension in initial_extensions:
       bot.load_extension(extension)


#---------------------------------------------------#
#Ready event htps
@bot.event
async def on_ready():
    change_status.start()
    print(f'Logged in as {bot.user} (ID: {bot.user.id})')
    print(datetime.datetime.now())
    print(f'Ping: {round(bot.latency * 1000)}ms')
    print('--------------------------------------------------------')


@bot.event
async def on_guild_join(guild):
    general = find(lambda x: x.name == 'general', guild.text_channels)
    embed = discord.Embed(title=("**Hello-{}!**".format(guild.name)),
                          colour=discord.Colour.dark_purple(),
                          description="Prefix[!]")
    embed.set_footer(text="Sheep™")
    if general and general.permissions_for(guild.me).send_messages:
        await general.send(embed=embed)


#----------------------commands-----------------------------------#
#Bot stop command - add embed
@bot.command(name='botstop', aliases=['bstop', 'end'])
@commands.is_owner()
async def botstop(ctx):
    print('Commiting sudoku')
    await ctx.send('I committed sudoku')
    await bot.logout()
    return


#Clear command
@bot.command(aliases=['purge', 'delete'])
@commands.has_permissions(manage_messages=True)
async def clear(ctx, amount: int):
    if amount == None:
        await ctx.channel.purge(limit=1000000)
    else:
        await ctx.channel.purge(limit=amount)


#Ping command - embed
@bot.command(name="ping", pass_context=True)
async def ping(ctx):
    embed = discord.Embed(title="**PING**",
                          colour=discord.Colour.dark_purple(),
                          description=(f'{round(bot.latency * 1000)}ms'))
    embed.set_footer(text="Sheep™")
    embed.set_author(name=ctx.author.display_name, icon_url=ctx.author.avatar)
    await ctx.send(embed=embed)


#Task loop for chg
@tasks.loop(seconds=2)
async def change_status():
    await bot.change_presence(activity=discord.Game(choice(status)))


#-------------------------Function startup------------------------#

keepalive()
bot.run(DISCORD_TOKEN)

Here is my code that is in the example cog.

#Library of imports
#---------------------------------------------------#
import discord
from discord.ext import commands
from discord import Message

#---------------------------------------------------#


#----------------------COG--------------------------#
class MyCog(commands.Cog):
    def __init__(self, bot):
        self.bot = bot

    #Default help command
    @commands.command()
    async def help(self, ctx):
        embed = discord.Embed(title="Sheep™",
                              url="https://youtu.be/EuGRKqTwbVI",
                              description="** **",
                              colour=discord.Colour.dark_purple())
        embed.set_author(name=ctx.author.display_name,
                         icon_url=ctx.author.avatar_url)
        embed.set_thumbnail(
            url=
            "https://www.visitliptov.sk/wp-content/uploads/2021/05/LIPTOV-LOGO_white-2048x2048.png"
        )

        embed.add_field(
            name="**HELP**",
            value="This command shows functions of every command. Prefix{!}",
            inline=False)
        embed.add_field(name="**Admin**",
                        value="|`Load`|`Unload`|`Reload`|`Status`|`Botstop`|",
                        inline=True)
        embed.add_field(name="**Fun**",
                        value="|`Embed`|`Sheep`|`Date`|",
                        inline=True)
        embed.add_field(name="**Misc**",
                        value="|`Ping`|`Uptime`|`Clear`|`Avatar`|",
                        inline=True)
        embed.add_field(name="**Music**", value="|`WIP`|", inline=False)
        embed.set_footer(text="Sheep™")
        await ctx.send(embed=embed)


def setup(bot):
    bot.add_cog(MyCog(bot))