Cannot connect to aiosmtpd server from non-localhost

I have an SMTP server set up using aiosmtpd, while I can use telnet to send SMTP emails on my own local machine; if I try to telnet to it from anywhere else, I get Could not open connection to the host, on port 8025: Connect failed (note: I have tried it with port 80, 25 and 8025). All those ports are forwarded, along with Windows Firewall being completely disabled. With logging.basicConfig(level=logging.DEBUG), I get the following log:

DEBUG:asyncio:Using proactor: IocpProactor
DEBUG:asyncio:Using proactor: IocpProactor
INFO:mail.log:Available AUTH mechanisms: LOGIN(builtin) PLAIN(builtin)
INFO:mail.log:Peer: ('::1', 50067, 0, 0)
INFO:mail.log:('::1', 50067, 0, 0) handling connection
SMTP server started...
DEBUG:mail.log:('::1', 50067, 0, 0) << b'220 EC2AMAZ-QCHL34E.eu-north-1.compute.internal Python SMTP 1.4.6'
INFO:mail.log:('::1', 50067, 0, 0) EOF received
INFO:mail.log:('::1', 50067, 0, 0) Connection lost during _handle_client()
INFO:mail.log:('::1', 50067, 0, 0) connection lost

./smtp_server.py:

import asyncio
from aiosmtpd.controller import Controller
import os
import logging

logging.basicConfig(level=logging.DEBUG)

class CustomSMTPHandler:
    def __init__(self, save_path='emails.txt'):
        self.save_path = save_path

    async def handle_DATA(self, server, session, envelope):
        print('Incoming message:')
        print(f'From: {envelope.mail_from}')
        print(f'To: {envelope.rcpt_tos}')
        print(f'Content: {envelope.content.decode("utf8", errors="replace")}')

        with open(self.save_path, 'a') as f:
            f.write(f'From: {envelope.mail_from}\n')
            f.write(f'To: {", ".join(envelope.rcpt_tos)}\n')
            f.write(f'Content: {envelope.content.decode("utf8", errors="replace")}\n')
            f.write(f'-----------------------\n')
        
        return '250 Message accepted for delivery'

async def main():
    if not os.path.exists('emails.txt'):
        open('emails.txt', 'w').close()

    handler = CustomSMTPHandler()
    controller = Controller(handler)
    controller.start()

    print('SMTP server started...')
    try:
        await asyncio.Event().wait()
    except KeyboardInterrupt:
        pass
    finally:
        controller.stop()

if __name__ == '__main__':
    asyncio.run(main())

I've triple-checked all port forwarding settings on both computers, and to see if its a port issue; I wrote a simple socket server in python to see if I could send data from another computer.

./test.py

import socket

HOST = '0.0.0.0'
PORT = 8025

with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as server_socket:
    server_socket.bind((HOST, PORT))
    server_socket.listen()
    print(f"Server listening on {PORT}...")

    conn, addr = server_socket.accept()
    with conn:
        print(f"Connection est w/ {addr}")
        while True:
            data = conn.recv(1024)
            if not data:
                break
            print(f"Incoming data: {data.decode()}")
            conn.sendall(data)

I could send data from the other computer to the computer that the aiosmtpd SMTP server is running on; and interestingly, I could start the test socket server even if the aiosmtpd SMTP server was still running.