126邮箱发126邮箱，没毛病，666

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

from email import encoders
from email.header import Header
from email.mime.text import MIMEText
from email.utils import parseaddr, formataddr
import smtplib


def _format_addr(s):
    name, addr = parseaddr(s)
    return formataddr((Header(name, 'utf-8').encode(), addr))

# 发件邮箱地址
from_addr = input('From: ')
# 此密码是POP3/SMTP/IMAP服务的授权码，并非邮箱客户端的登录密码
password = input('Password: ')
# 收件邮箱地址
to_addr = input('To: ')
# 发件服务器地址：例如smtp.126.com
smtp_server = input('SMTP server: ')

msg = MIMEText('hello, send by Python...', 'plain', 'utf-8')
msg['From'] = _format_addr('Python爱好者 <%s>' % from_addr)
msg['To'] = _format_addr('管理员 <%s>' % to_addr)
msg['Subject'] = Header('来自SMTP的问候……', 'utf-8').encode()

server = smtplib.SMTP(smtp_server, 25)
server.set_debuglevel(1)
server.login(from_addr, password)
server.sendmail(from_addr, [to_addr], msg.as_string())
server.quit()