My discord bot won't run, all i'm getting is a long error?

I wrote a Discord bot two years ago (with the async branch of discord.py) and I am trying to rewrite it right now. But every time I try to run the very simple code (it's supposed to print "Bot is ready" in the Python shell once it's up), I get this super long error message i have no idea what to do with. Can anyone help?

This is the error message:

Traceback (most recent call last):
  File "C:\Users\sepp66\AppData\Local\Programs\Python\Python38\lib\site-packages\aiohttp\connector.py", line 936, in _wrap_create_connection
    return await self._loop.create_connection(*args, **kwargs)  # type: ignore  # noqa
  File "C:\Users\sepp66\AppData\Local\Programs\Python\Python38\lib\asyncio\base_events.py", line 1050, in create_connection
    transport, protocol = await self._create_connection_transport(
  File "C:\Users\sepp66\AppData\Local\Programs\Python\Python38\lib\asyncio\base_events.py", line 1080, in _create_connection_transport
    await waiter
  File "C:\Users\sepp66\AppData\Local\Programs\Python\Python38\lib\asyncio\sslproto.py", line 529, in data_received
    ssldata, appdata = self._sslpipe.feed_ssldata(data)
  File "C:\Users\sepp66\AppData\Local\Programs\Python\Python38\lib\asyncio\sslproto.py", line 189, in feed_ssldata
    self._sslobj.do_handshake()
  File "C:\Users\sepp66\AppData\Local\Programs\Python\Python38\lib\ssl.py", line 944, in do_handshake
    self._sslobj.do_handshake()
ssl.SSLCertVerificationError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: certificate has expired (_ssl.c:1123)

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

Traceback (most recent call last):
  File "E:/Programmieren/GavBot 2.0/GavBot.py", line 13, in <module>
    client.run("NzUxODM5NzE0ODQ3NDkwMDY5.X1O7TA.3zxpKURW1fIaAUZF2ML2x0bjy2s")
  File "C:\Users\sepp66\AppData\Local\Programs\Python\Python38\lib\site-packages\discord\client.py", line 678, in run
    return future.result()
  File "C:\Users\sepp66\AppData\Local\Programs\Python\Python38\lib\site-packages\discord\client.py", line 658, in runner
    await self.start(*args, **kwargs)
  File "C:\Users\sepp66\AppData\Local\Programs\Python\Python38\lib\site-packages\discord\client.py", line 621, in start
    await self.login(*args, bot=bot)
  File "C:\Users\sepp66\AppData\Local\Programs\Python\Python38\lib\site-packages\discord\client.py", line 472, in login
    await self.http.static_login(token.strip(), bot=bot)
  File "C:\Users\sepp66\AppData\Local\Programs\Python\Python38\lib\site-packages\discord\http.py", line 288, in static_login
    data = await self.request(Route('GET', '/users/@me'))
  File "C:\Users\sepp66\AppData\Local\Programs\Python\Python38\lib\site-packages\discord\http.py", line 185, in request
    async with self.__session.request(method, url, **kwargs) as r:
  File "C:\Users\sepp66\AppData\Local\Programs\Python\Python38\lib\site-packages\aiohttp\client.py", line 1012, in __aenter__
    self._resp = await self._coro
  File "C:\Users\sepp66\AppData\Local\Programs\Python\Python38\lib\site-packages\aiohttp\client.py", line 480, in _request
    conn = await self._connector.connect(
  File "C:\Users\sepp66\AppData\Local\Programs\Python\Python38\lib\site-packages\aiohttp\connector.py", line 523, in connect
    proto = await self._create_connection(req, traces, timeout)
  File "C:\Users\sepp66\AppData\Local\Programs\Python\Python38\lib\site-packages\aiohttp\connector.py", line 858, in _create_connection
    _, proto = await self._create_direct_connection(
  File "C:\Users\sepp66\AppData\Local\Programs\Python\Python38\lib\site-packages\aiohttp\connector.py", line 1004, in _create_direct_connection
    raise last_exc
  File "C:\Users\sepp66\AppData\Local\Programs\Python\Python38\lib\site-packages\aiohttp\connector.py", line 980, in _create_direct_connection
    transp, proto = await self._wrap_create_connection(
  File "C:\Users\sepp66\AppData\Local\Programs\Python\Python38\lib\site-packages\aiohttp\connector.py", line 938, in _wrap_create_connection
    raise ClientConnectorCertificateError(
aiohttp.client_exceptions.ClientConnectorCertificateError: Cannot connect to host discord.com:443 ssl:True [SSLCertVerificationError: (1, '[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: certificate has expired (_ssl.c:1123)')]

This is my code:

from discord.ext import commands

client = commands.Bot(command_prefix="g!")

@client.event
async def on_ready():
    print("Bot is ready")

client.run(token)

Does anyone have any idea what is causing the exception?