ASP.net联系表发送电子邮件错误

Question

我真的需要一件事的帮助。 我有一个网站，在该网站中，我有一个与我们联系的页面，用户可以在其中与该页面或任何其他内容的管理员联系。

问题是当我尝试呈现页面时，它给我一个错误提示

The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required. Learn more at
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Net.Mail.SmtpException: The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required. Learn more at

Source Error:


Line 21:         smtp.Credentials = NetworkCred
Line 22:         smtp.Port = 587
Line 23:         smtp.Send(mm)
Line 24:         lblMessage.Text = "Email Sent SucessFully."
Line 25:     End Sub


Source File: C:\Users\user\Desktop\ContactUsForm\VB.aspx.vb    Line: 23 

我真的不知道该怎么做。 我的VB背后的代码是：

Imports System.Net
Imports System.Net.Mail
Partial Class VB
    Inherits System.Web.UI.Page
    Protected Sub btnSend_Click(ByVal sender As Object, ByVal e As EventArgs)
        Dim mm As New MailMessage("sender@gmail.com", "reveiver@gmail.com")
        mm.Subject = txtSubject.Text
        mm.Body = "Name: " & txtName.Text & "<br /><br />Email: " & txtEmail.Text & "<br />" & txtBody.Text
        If FileUpload1.HasFile Then
            Dim FileName As String = System.IO.Path.GetFileName(FileUpload1.PostedFile.FileName)
            mm.Attachments.Add(New Attachment(FileUpload1.PostedFile.InputStream, FileName))
        End If
        mm.IsBodyHtml = True
        Dim smtp As New SmtpClient()
        smtp.Host = "smtp.gmail.com"
        smtp.EnableSsl = True
        Dim NetworkCred As New System.Net.NetworkCredential()
        NetworkCred.UserName = "sender@gmail.com"
        NetworkCred.Password = "senderpassword"
        smtp.UseDefaultCredentials = True
        smtp.Credentials = NetworkCred
        smtp.Port = 587
        smtp.Send(mm)
        lblMessage.Text = "Email Sent SucessFully."
    End Sub
End Class

错误在第23行显示smtp.Send（mm）

我真的很需要 请任何人能帮助我。

Answer 1

更改

smtp.UseDefaultCredentials = False

您不想使用默认凭据，而要使用在代码中创建的凭据。

https://msdn.microsoft.com/zh-cn/library/system.net.mail.smtpclient.usedefaultcredentials(v=vs.110).aspx