Gmail错误:SMTP服务器需要安全连接或客户端未经过身份验证。服务器的响应是:5.5.1需要身份验证

我正在使用以下代码发送电子邮件。代码在我的本地机器上正常工作。但是在生产服务器上，我得到了错误消息

var fromAddress = new MailAddress("mymailid@gmail.com");
var fromPassword = "xxxxxx";
var toAddress = new MailAddress("yourmailid@yourdoamain.com");

string subject = "subject";
string body = "body";

System.Net.Mail.SmtpClient smtp = new System.Net.Mail.SmtpClient
{
    Host = "smtp.gmail.com",
    Port = 587,
    EnableSsl = true,
    DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.Network,
    UseDefaultCredentials = false,
    Credentials = new NetworkCredential(fromAddress.Address, fromPassword)       
};

using (var message = new MailMessage(fromAddress, toAddress)
{
    Subject = subject,
    Body = body
})

smtp.Send(message);

在我的Gmail A/c上，我从生产服务器运行代码后收到了以下电子邮件

Hi , Someone recently used your password to try to sign in to your Google Account mymailid@gmail.com. This person was using an application such as an email, client or mobile device. We prevented the sign-in attempt in case this was a hijacker trying to access your account. Please review the details of the sign-in attempt: Friday, 3 January 2014 13:56:08 o'clock UTC IP Address: xxx.xx.xx.xxx (abcd.net.) Location: Philadelphia PA, Philadelphia, PA, USA If you do not recognise this sign-in attempt, someone else might be trying to access your account. You should sign in to your account and reset your password immediately. Reset password If this was you and you are having trouble accessing your account, complete the troubleshooting steps listed at http://support.google.com/mail?p=client_login Yours sincerely, The Google Accounts team

当前回答

我在部署到Microsoft Azure的应用程序中遇到了同样的问题。

SmtpException: SMTP服务器需要安全连接，或者SMTP服务器需要安全连接客户端未被验证。服务器的响应是:5.5.1 认证要求。

首先，我在以下页面上批准了所有未知设备(一些来自爱尔兰的ip地址)(以gmail用户登录): https://security.google.com/settings/u/1/security/secureaccount

我对客户端进行了如下设置:

var client = new SmtpClient("smtp.gmail.com");
client.Port = 587;
client.EnableSsl = true;
client.UseDefaultCredentials = false;
client.Credentials = new NetworkCredential("my_user_name@gmail.com", "my_password");

只有当我在smtp-client上设置了以下属性后，它才开始工作:

client.TargetName = "STARTTLS/smtp.gmail.com";

2015-09-11 12:38:50

其他回答

对我有效的是激活不太安全的应用程序的选项(我使用VB.NET)

Public Shared Sub enviaDB(ByRef body As String, ByRef file_location As String)
        Dim mail As New MailMessage()
        Dim SmtpServer As New SmtpClient("smtp.gmail.com")
        mail.From = New MailAddress("from@gmail.com")
        mail.[To].Add("to@gmail.com")
        mail.Subject = "subject"
        mail.Body = body
        Dim attachment As System.Net.Mail.Attachment
        attachment = New System.Net.Mail.Attachment(file_location)
        mail.Attachments.Add(attachment)
        SmtpServer.Port = 587
        SmtpServer.Credentials = New System.Net.NetworkCredential("user", "password")
        SmtpServer.EnableSsl = True
        SmtpServer.Send(mail)
    End Sub

所以登录你的账户，然后去 google.com/settings/security/lesssecureapps

2015-12-02 21:39:03

Tomasz Madeyski的评论解决了我的问题…他告诉存在一个错误的SetDefaultCredential，他说:

问题是在UseDefaultCredentials setter中有这样的代码:this.transport. credentials = value ?(ICredentialsByHost) CredentialCache。DefaultNetworkCredentials: (ICredentialsByHost) null;它覆盖由凭证设置器设置的凭证。对我来说，它看起来像SmtpClient的bug。”

如果你输入smtpClient。设置凭证后UseDefaultCredentials = false…这一行设置为空这些凭据…

2018-02-23 10:21:33

2018年11月，我尝试了以上所有方法，但都没有成功。

下面是最终有效的解决方案。不幸的是，它不使用SSL，但它工作!!

var fromAddress = new MailAddress(asd@asd.com, "From Name");
var toAddress = new MailAddress("tosend@asd.com", "To Name");

const string subject = "Subject";
const string body = "Body";

var smtp = new SmtpClient
{
    Host = "aspmx.l.google.com",
    Port = 25,
    EnableSsl = false
};
using (var message = new MailMessage(fromAddress, toAddress)
{
    Subject = subject,
    Body = body
})
{
    smtp.Send(message);
}

2018-11-29 16:52:59

更新2022

更不安全的应用程序方法不再工作

您应该迁移到GMail SMTP API

仅使用gmail id和密码发送电子邮件不再有效。您必须从谷歌云控制台设置api并创建OAuth凭据。

链接到谷歌云控制台

连结至官方指南

链接到一个简单的指南

原来的答案

这是一个安全问题。Gmail默认情况下阻止自定义应用程序访问您的电子邮件帐户。您可以将其设置为接受应用程序的登录。

登录您的电子邮件后，点击这里

这将带您到下面的页面