用smtplib通过python自动发送电子邮件，使用从gmail发送到iusd (学区)，无法通过

import smtplib
from email.mime.text import MIMEText

# 邮件内容
subject = "这是一封测试邮件"
body = "这是一封通过Python自动发送的测试邮件。"
sender = "your_email@gmail.com"
receiver = "iusd@example.com"

# 创建邮件对象
msg = MIMEText(body, "plain")
msg["Subject"] = subject
msg["From"] = sender
msg["To"] = receiver

# 发送邮件
try:
    # 连接到发件人的邮箱服务器
    smtp_server = "smtp.gmail.com"
    smtp_port = 587
    smtp_username = "your_email@gmail.com"
    smtp_password = "your_password"
    smtp_connection = smtplib.SMTP(smtp_server, smtp_port)
    smtp_connection.starttls()
    smtp_connection.login(smtp_username, smtp_password)

    # 发送邮件
    smtp_connection.sendmail(sender, receiver, msg.as_string())
    print("邮件发送成功！")

    # 关闭连接
    smtp_connection.quit()
except Exception as e:
    print("邮件发送失败：", str(e))