如何使用VB.NET从Outlook帐户发送电子邮件？

How do I use VB.NET to send an email from an Outlook account?

我正在尝试通过vb.net程序通过Outlook电子邮件帐户发送电子邮件。运行代码时，我收到一条错误消息，提示我没有安全连接。我一直在网上搜索，并尝试了所有发现的调整，但是仍然没有运气。

这是我目前的代码(更改了特定的电子邮件地址和密码)：

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Private Sub LEmail_Click(sender As Object, e As EventArgs) Handles LEmail.Click
Try
Dim SmtpServer As New SmtpClient("smtp.outlook.com")
Dim mail As New MailMessage()
SmtpServer.Credentials = New Net.NetworkCredential("[email protected]","Password")
SmtpServer.Port = 587
SmtpServer.EnableSsl = True
mail = New MailMessage()
mail.From = New MailAddress("[email protected]")
mail.To.Add("[email protected]")
mail.Subject ="Test Mail"
mail.Body ="This is for testing SMTP mail from OUTLOOK"
SmtpServer.UseDefaultCredentials = False
SmtpServer.Send(mail)
MessageBox.Show("mail sent")
Catch ex As Exception
MsgBox(ex.ToString)
End Try
End Sub

任何建议和帮助将不胜感激。谢谢：)

编辑：我也尝试过SmtpServer.Port = 25

编辑2：错误消息显示：

System.Net.Mail.SmtpExeption: The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.7.57 SMTP; Client was not authenticated to send anonymous mail during MAIL FROM as System.Net.Mail.MailCommand.CheckResponse(SmtpStatusCode statusCode, String response) at System.Net.Mail.MailCommand.Sent(SmtpConnection conn, Byte[] command, MailAddress from, Boolean allowUnicode) at System.Net.Mail.SmtpTransport.SendMail(MailAddress sender, MailAddressCollection recipients, String deliveryNotify, Boolean allowUnicode, SmtpFailedRecipientException& exception) at System.Net.Mail.SmtpClient.Send(MailMessage message) at WindowsApplication.Form1.LEmail_Click(Object sender, EventArgs e) in C:\\Users\\Monica\\Documents\\Current\\Visual Studio\\WindowsApplication\\Form1.vb:line 553

编辑3：第二个错误：

System.Net.Mail.SmtpException: Mailbox unavailable. The server response was: 5.3.4 Requested action not taken; We noticed some unusual activity in your Hotmail account. To help protect you, we've temporarily blocked your account. at System.Net.Mail.DataStopCommand.CheckResponse(SmtpStatusCode statusCode, String serverResponse) at System.Net.Mail.DataStopCommand.Send(SmtpConnection conn) at System.Net.Mail.SmtpConnection.OnClose(Object sender, EventArgs args) at System.Net.CloseableStream.Close() at System.Net.MailWriter.Close() at System.Net.Mail.SmtpClient.Send(MailMessage message) at WindowsApplication.Form1.LEmail_Click(Object sender, EventArgs e) in C:\\User\\Monica\\Documents\\Current\\Visual Studio\\WindowsApplication\\Form1.vb:line 553