Question

我正在尝试在Intranet上发送邮件。我设计了一个页面，其中的值将从文本框中接受，并传递到相应的字段。

这是我的前端代码（请忽略<tr>和<td>代码）：

<td>
    FROM
</td>
<td>
<asp:TextBox ID="txtFrom" runat="server" CssClass="Textbox1" Width="414px"></asp:TextBox>
</td>
<td>
    SENDER MAIL
</td>
<td>
<asp:TextBox ID="txtMailAdd" runat="server" CssClass="Textbox1" Width="414px"></asp:TextBox>
<td>
    SMTP IP
</td>
<td>
<asp:TextBox ID="txtSMTP" runat="server" CssClass="Textbox1" Width="414px"></asp:TextBox>
<td>
   RECEIVER
</td>
<td>
<asp:TextBox ID="txtReceiver" runat="server" CssClass="Textbox1" Width="414px"></asp:TextBox>
<td>
    TO MAIL
</td>
<td>
<asp:TextBox ID="txtTo" runat="server" CssClass="Textbox1" Width="414px"></asp:TextBox>

这是我的后端代码：

protected void btnSMail_Click(object sender, EventArgs e)
{
    string smtpadd = txtSMTP.Text;

    try
    {
        if (smtpadd != "" && smtpadd != null)
        {
            MailMessage mm = new MailMessage();
            SmtpClient sc = new SmtpClient(txtSMTP.Text);

            if (!fupAttach.HasFile)
            {
                FileStream fs = new FileStream("D:\\DEV\\New.xml", FileMode.Open, FileAccess.Read);
                Attachment attch = new Attachment(fs, "License Generation in XML", MediaTypeNames.Application.Octet);
                mm.Attachments.Add(attch);
            }

            //sc.Host = "10.8.4.118";
            sc.Port = 25;
            sc.EnableSsl = false; // runtime encrypt the SMTP communications using SSL

            mm.To.Add(new MailAddress(txtTo.Text, txtReceiver.Text));
            mm.From = new MailAddress(txtMailAdd.Text, txtFrom.Text);
            mm.Subject = txtSub.Text;
            //mm.To= new MailAddress(txtTo.Text);
            mm.Body = txtBody.Text;

            if (fupAttach.HasFile)
            {
                String FileName = fupAttach.PostedFile.FileName;
                Attachment mailAttachment = new Attachment(FileName, MediaTypeNames.Application.Octet);
                mm.Attachments.Add(mailAttachment); 
            }

            lblMailFail.Text = "Mail Successfully Sent";

            sc.Send(mm);
        }

        else
        {
            lblMailFail.Text = "Enter an SMTP IP";
        }
    }

现在，当我尝试在文本框中输入以下值时

Sender Mail: xyz@sdc.ba.co.in
SMTP ID: 10.8.4.2
Receiver Mail: xyz@sdc.ba.co.in

我收到错误

System.Net.Mail.SmtpFailedRecipientException: Mailbox unavailable. The server response was: 5.7.1 Unable to relay for xyz@sdc.ba.co.in at System.Net.Mail.SmtpTransport.SendMail(MailAddress sender, MailAddressCollection recipients, String deliveryNotify, SmtpFailedRecipientException& exception) at System.Net.Mail.SmtpClient.Send(MailMessage message) at Lic_Gen.btnSMail_Click(Object sender, EventArgs e)

有人可以指导我哪里出错了吗？

Answer 1

这是一个SMTP配置问题，与您的C＃代码无关。

Answer 2

邮件服务器不允许您（或您的IP）将邮件发送到指定的电子邮件地址。您可以对邮件服务器here进行详细测试。

您可以在Eudora website上找到有关邮件中继的更多信息（大部分信息适用于所有邮件服务器）

SMTP邮件无法正常工作

2 个答案: