使用启用 TLS 的服务器以 VB.Net 发送电子邮件

Question

我正在开发用于发送启用TLS的SMTP服务器的电子邮件的应用程序，我想在Windows Server 2003上运行此应用程序。当我在窗口服务器 2012 R2 上运行相同的应用程序时，它工作得很好，但它在窗口服务器 2003 上不起作用。有什么具体原因无法在窗口服务器 2003 上运行吗？

错误：SMTP 服务器需要安全连接或客户端未经过身份验证。服务器响应为：5.7.1 客户端未通过身份验证。

我在应用程序中使用了以下代码：

Public Sub sendemail()
Dim SMTPMailServer As New System.Net.Mail.SmtpClient("xyz") 'tls enabled SMTP Server Name 
Dim myMail As System.Net.Mail.MailMessage = New System.Net.Mail.MailMessage("FromEmail", "ToEmail")
With myMail
.Subject = "Test Email with TLS enabled server"
.Body = "Test Body"
.Priority = Net.Mail.MailPriority.Normal
.IsBodyHtml = True
End With
SMTPMailServer.Send(myMail)
myMail = Nothing
End Sub

Answer 1

Imports System.Net.Mail
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, _
ByVal e As System.EventArgs) Handles Button1.Click
Try
Dim SmtpServer As New SmtpClient()
Dim mail As New MailMessage()
SmtpServer.Credentials = New _
Net.NetworkCredential("[e-mail]", "password")
SmtpServer.Port = 587
SmtpServer.Host = "smtp.gmail.com"
mail = New MailMessage()
mail.From = New MailAddress("[e-mail]")
mail.To.Add("TOADDRESS")
mail.Subject = "Test Mail"
mail.Body = "This is for testing SMTP mail from GMAIL"
SmtpServer.Send(mail)
MsgBox("mail send")
Catch ex As Exception
MsgBox(ex.ToString)
End Try
End Sub
End Class