使用Python smtplib库发送Gmail邮件出现WinError10060超时错误求助

原始问题代码 #

import smtplib

connection = smtplib.SMTP("smtp.gmail.com")
connection.starttls()
connection.login(user="mymail@gmail.com", password="mypassowrd")
connection.sendmail(from_addr="mymail@gmail.com", to_addrs="recievermail@gmail.com", msg="Hello")
connection.close()

运行抛出的错误栈 #

Traceback (most recent call last):
  File "E:\100Days-Python_programs\Day32\Birthday Wisher (Day 32) start\main.py", line 3, in <module>
    connection = smtplib.SMTP("smtp.gmail.com")
  File "C:\Users\HP\AppData\Local\Programs\Python\Python39\lib\smtplib.py", line 253, in __init__
    (code, msg) = self.connect(host, port)
  File "C:\Users\HP\AppData\Local\Programs\Python\Python39\lib\smtplib.py", line 339, in connect
    self.sock = self._get_socket(host, port, self.timeout)
  File "C:\Users\HP\AppData\Local\Programs\Python\Python39\lib\smtplib.py", line 310, in _get_socket
    return socket.create_connection((host, port), timeout,
  File "C:\Users\HP\AppData\Local\Programs\Python\Python39\lib\socket.py", line 843, in create_connection
    raise err
  File "C:\Users\HP\AppData\Local\Programs\Python\Python39\lib\socket.py", line 831, in create_connection
    sock.connect(sa)
TimeoutError: [WinError 10060] A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond

Process finished with exit code 1

已完成的排查操作 #

• 开启Google账号的低安全性应用访问权限
• 关闭Google账号的所有附加安全验证步骤
• 关闭本地系统防火墙防护
  以上操作均未解决连接超时问题。

可落地的解决步骤 #

• 修正端口参数配置
  smtplib初始化SMTP连接时不指定端口的话，默认使用25端口。该端口在绝大多数家庭、办公网络环境下会被运营商或网关拦截，根本无法连通Gmail服务器。Gmail的TLS加密连接必须显式指定587端口，SSL直连必须指定465端口，不能依赖默认端口参数。
• 调整代码连接逻辑
  修正后的可参考代码：

  import smtplib
  # 显式指定587端口，延长超时阈值避免快速触发超时
  connection = smtplib.SMTP("smtp.gmail.com", port=587, timeout=30)
  connection.starttls()
  connection.login(user="mymail@gmail.com", password="你的专属应用授权密码")
  connection.sendmail(from_addr="mymail@gmail.com", to_addrs="recievermail@gmail.com", msg="Hello")
  connection.close()
  

• 匹配账号认证规则
  Google从2022年起已彻底关闭“低安全性应用访问”通道，不再支持使用账号本身的登录密码直接做SMTP认证。无论是否关闭账号附加安全验证，都需要在Google账号后台生成16位的专属应用授权密码，替换代码中的普通登录密码，才能通过认证环节。
• 校验网络连通性
  如果本地网络无法直连Gmail的境外SMTP服务，哪怕端口和配置全部正确也会触发10060超时。可在系统命令行执行telnet smtp.gmail.com 587校验连通性，如果返回连接失败，说明当前网络出口无法直达目标服务，需要为Python进程配置可用的网络代理后再做调试。

内容的提问来源于stack exchange，提问作者Deep Shah