GitHub cannot authorize with oauth

I'm trying to make a GitHub bot that posts issues when a complementary app throws errors, but I'm having trouble trying to get an access token. This is my code so far:

import asyncio
import random
import webbrowser

import aiohttp.web

randgen = random.SystemRandom()


# The task is relatively simple. Query for the client ID, client secret, and then produces a URL.
# It opens this URL in a web-browser, then sets up a server on port 12345, waiting for an appropriate response.
# Using this code, it finishes the rest of the flow.

class Authorizer:
    def __init__(self):
        self.client_id = self.client_secret = ""
        self.redirect_url = "http://localhost:12345/callback"
        self.scopes = ["public_repo"]
        self.state = 0
        self.done = False

    async def handler(self, request: aiohttp.web.Request):
        code = request.query["code"]
        async with aiohttp.ClientSession() as client:
            async with client.post("https://github.com/login/oauth/access_token",
                                   data=dict(client_id=self.client_id, client_secret=self.client_secret, code=code, state=self.state),
                                   headers=dict(Accept="application/json")) as request:
                json = await request.json()
                assert str(json["state"]) == self.state
                resp = "Access Token: " + json["access_token"]
                print(resp)
                self.done = True
                return aiohttp.web.Response(text=resp)

    async def start(self):
        self.client_id = input("App Client ID: ")
        self.client_secret = input("App Client Secret: ")
        self.state = randgen.randint(1, 1000)
        scope_str = ' '.join(self.scopes)
        url = f"https://github.com/login/oauth/authorize?client_id={self.client_secret}&redirect_uri={self.redirect_url}&scope=" \
              f"{scope_str}&state={self.state}"
        print("Opening URL: " + url)
        webbrowser.open(url)
        self.server = aiohttp.web.Server(self.handler)
        self.runner = aiohttp.web.ServerRunner(self.server)
        await self.runner.setup()
        self.site = aiohttp.web.TCPSite(self.runner, 'localhost', 12345)
        await self.site.start()
        while not self.done:
            await asyncio.sleep(1)
        await self.site.stop()
        input("Complete! Make sure you take your access token with you! Now hit enter to exit.")


if __name__ == '__main__':
    auth = Authorizer()
    loop = asyncio.get_event_loop()
    loop.run_until_complete(auth.start())

I get an error, where the constructed URL gives me a 404 error. Getting rid of the state, redirect URL, and scopes don't change the error. I looked at the official docs when making this, so I don't understand why the constructed error is giving me a 404.