关于office365：无法使用c#SmtpClient从Office 365发送电子邮件

Unable to send email from Office 365 using c# SmtpClient

尝试使用SmtpClient从c#中的Winforms应用发送电子邮件。通过这篇MS文章，它应该可以工作。我搜索了许多论坛等，但没有找到任何解决方案。该错误消息似乎表明客户端未通过身份验证。密码是正确的，我已经以该用户身份使用该密码登录并可以正常使用。 2FA已启用，但htis应该不会妨碍它？

我检查过的东西都在适当的地方

启用S??Sl

来自电子邮件和用户电子邮件是相同的

587端口

我有这个帐户，前景很好

防火墙没有阻止此端口。我还有其他代码使用与非O365主机完全相同的代码，并且工作正常

代码

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18

var userName ="[email protected]";
var password ="password";
var msg = new MailMessage();
msg.To.Add(new MailAddress("[email protected]"));
msg.From = new MailAddress(userName);
msg.Subject ="Test Office 365 Account";
msg.Body ="Testing email using Office 365 account.";
msg.IsBodyHtml = true;

var client = new SmtpClient{
Host ="smtp.office365.com",
Credentials = new System.Net.NetworkCredential(userName, password),
Port = 587,
DeliveryMethod = SmtpDeliveryMethod.Network,
EnableSsl = true
};

client.Send(msg);

异常

SMTP服务器需要安全连接，否则客户端将无法连接
已验证。服务器响应为：5.7.57 SMTP；客户不是
经过验证可在MAIL FROM期间发送匿名邮件

邮件工具包的实施(建议vasily.sib)

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25

var message = new MimeMessage();
message.From.Add(new MailboxAddress("Test User","[email protected]"));
message.To.Add(new MailboxAddress("Gmail User","[email protected]"));
message.Subject ="test";

message.Body = new TextPart("plain")
{
Text = @"test"
};

var client = new SmtpClient(new ProtocolLogger("imap.log"));

// For demo-purposes, accept all SSL certificates (in case the server supports STARTTLS)
client.ServerCertificateValidationCallback = (s, c, h, e) => true;

client.Connect("smtp.office365.com", 587, SecureSocketOptions.Auto); //this is fine and it connects

var clientAuthenticationMechanisms = client.AuthenticationMechanisms;
client.AuthenticationMechanisms.Remove("XOAUTH2");
// Note: only needed if the SMTP server requires authentication
client.Authenticate("[email protected]","password"); // this is where it fails with Authentication Failure

client.Send(message);
client.Disconnect(true);

邮件工具包日志输出

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29

Connected to smtp://smtp.office365.com:587/?starttls=when-available
S: 220 SYCP282CA0015.outlook.office365.com Microsoft ESMTP MAIL Service ready at Mon, 25 Nov 2019 04:49:36 +0000
C: EHLO [192.168.2.50]
S: 250-SYCP282CA0015.outlook.office365.com Hello [58.6.92.82]
S: 250-SIZE 157286400
S: 250-PIPELINING
S: 250-DSN
S: 250-ENHANCEDSTATUSCODES
S: 250-STARTTLS
S: 250-8BITMIME
S: 250-BINARYMIME
S: 250-CHUNKING
S: 250 SMTPUTF8
C: STARTTLS
S: 220 2.0.0 SMTP server ready
C: EHLO [192.168.2.50]
S: 250-SYCP282CA0015.outlook.office365.com Hello [58.6.92.82]
S: 250-SIZE 157286400
S: 250-PIPELINING
S: 250-DSN
S: 250-ENHANCEDSTATUSCODES
S: 250-AUTH LOGIN XOAUTH2
S: 250-8BITMIME
S: 250-BINARYMIME
S: 250-CHUNKING
S: 250 SMTPUTF8
C: AUTH LOGIN
REMOVED BASE64 DATA (password, login)
S: 535 5.7.3 Authentication unsuccessful [SYCP282CA0015.AUSP282.PROD.OUTLOOK.COM]