使用 SMTP 发送邮件时连接意外异常

Question

我尝试使用 SMTP 发送电子邮件并遇到“连接意外关闭”异常。我已经检查了所有参数，包括 SMTP 服务器地址和端口。我使用的是从我的 Google 帐户设置生成的密码，并且已确保“使用两步验证登录”已开启。尽管进行了这些检查，我仍然面临这个问题。我将不胜感激任何有关解决此问题的帮助或见解。

`from email.message import EmailMessage
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText
import time
import ssl
import smtplib




# Email configuration
sender_email = my_email
app_password = my_password #generated from my Google Account settings

receiver_email = some_email


subject = 'Test Email'
body = 'This is a test email sent using smtplib in Python.'


# Create message
em = EmailMessage()
em['From'] = sender_email
em['To'] = receiver_email
em['Subject'] = subject
em.set_content(body)


# Gmail SMTP server configuration
smtp_server = 'smtp.gmail.com'
smtp_port = 465 


max_retries = 3
retry_delay_seconds = 5

for attempt in range(1, max_retries + 1):
    try:
        # Connect to the SMTP server
        with smtplib.SMTP(smtp_server, smtp_port) as smtp:
    # Log in
            smtp.login(sender_email, app_password)

    # Send mail
            smtp.sendmail(sender_email, receiver_email, em.as_string())

        print("Email sent successfully!")
        break  # Exit the loop if successful

    except smtplib.SMTPServerDisconnected as e:
        print(f"Attempt {attempt}: SMTPServerDisconnected - {e}")
        if attempt < max_retries:
            print(f"Retrying in {retry_delay_seconds} seconds...")
            time.sleep(retry_delay_seconds)
        else:
            print("Maximum retries reached. Exiting.")
            raise

    except Exception as e:
        print(f"Unexpected error: {e}")
        raise`

Answer 1

让我们一步步解决这个问题。

1 SMTP 类别和端口的正确使用：

• 您的代码使用

  smtplib.SMTP

  连接到 Gmail 的 SMTP 服务器。但是，对于使用 SSL 的安全连接（这是 Gmail 所要求的），您应该使用

  smtplib.SMTP_SSL

  。

• SSL 连接端口已正确设置为 465。只需确保您使用 SMTP_SSL 来匹配此端口即可。

2 SMTP_SSL 代码修订：

以下是修改代码的方法：

import smtplib
from email.message import EmailMessage

# Email configuration
sender_email = 'my_email'
app_password = 'my_password'  # App password generated from Google Account settings
receiver_email = 'some_email'

# Create the email message
em = EmailMessage()
em['From'] = sender_email
em['To'] = receiver_email
em['Subject'] = 'Test Email'
em.set_content('This is a test email sent using smtplib in Python.')

# Gmail SMTP server configuration for SSL
smtp_server = 'smtp.gmail.com'
smtp_port = 465  # Port for SSL

try:
    with smtplib.SMTP_SSL(smtp_server, smtp_port) as smtp:
        smtp.login(sender_email, app_password)
        smtp.send_message(em)
    print("Email sent successfully!")
except Exception as e:
    print(f"An error occurred: {e}")