c# – 发送邮件表单异常：System.Runtime.InteropServices.COMEx

System.Runtime.InteropServices.COMException: ??? ?????? “SendUsing”
???? ?÷?.

可能是什么问题呢？

这是我的代码：

<%@ Import Namespace="System.Web.Mail" %>

<script language="c#" runat="server">
    protected void Button2_Click(object sender,EventArgs e)
    {
        MailMessage msg = new MailMessage();

        msg.To = "XXX@gmail.com";

        msg.From = EmailTxt.Text;

        msg.Subject = "Fun With Daniel Email: from" + UsernameTxt.Text;

        msg.Body = MessegeBox.Text;
        msg.BodyFormat = MailFormat.Text;
        ErrorMessege.Text = "Sending..";


        System.Web.Mail.SmtpMail.Send(msg);

        ErrorMessege.Text = "The Email Sent successfully!";



    }

</script>

<td>
                                <asp:TextBox ID="UsernameTxt" runat="server"></asp:TextBox>
                                <asp:RequiredFieldValidator ID="RequiredFieldValidator10" runat="server" ErrorMessage="Please insert a Username"
                                    ControlToValidate="UsernameTxt" ForeColor="Red" Display="None" 
                                    SetFocusOnError="True"></asp:RequiredFieldValidator>
                            </td>
                        </tr>
                        <tr>
                            <td>
                                Email
                            </td>
                            <td>
                                <asp:TextBox ID="EmailTxt" runat="server"></asp:TextBox>
                                <asp:RequiredFieldValidator ID="RequiredFieldValidator11" runat="server" ErrorMessage="Please insert Password"
                                    ControlToValidate="EmailTxt" ForeColor="Red" Display="None" 
                                    SetFocusOnError="True"></asp:RequiredFieldValidator>
                            </td>
                        </tr>
                        <tr>
                            <td>
                                Messege
                            </td>
                            <td>
                                <asp:TextBox ID="MessegeBox" runat="server" Height="100px" TextMode="MultiLine"></asp:TextBox>
                                <asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" ErrorMessage="You have to write a messege"
                                    ControlToValidate="MessegeBox" ForeColor="Red" Display="None" 
                                    SetFocusOnError="True"></asp:RequiredFieldValidator>
                            </td>
                        </tr>
                        <tr>
                            <td>
                                <asp:Button ID="Button2" runat="server" Text="Login" OnClick="Button2_Click" />

                            </td>
                            <td>

                                <asp:Label ID="ErrorMessege" runat="server" ForeColor="Red"></asp:Label>
                                <asp:ValidationSummary ID="ValidationSummary2" runat="server" ForeColor="Red" />
                            </td>

                        </tr>