C＃asp.net电子邮件发送失败！服务器响应为：5.5.1需要身份验证

Question

我正尝试从我的asp.net网站发送电子邮件。

protected void btnSend_Click(object sender, EventArgs e)
        {
            try
            {
                //Create Mail Message Object with content that you want to send with mail.
                System.Net.Mail.MailMessage mailMessage = new System.Net.Mail.MailMessage(txtFrom.Text, txtTo.Text, txtSubject.Text, txtMessage.InnerText);
                mailMessage.IsBodyHtml = false;
                //Proper Authentication Details need to be passed when sending email from gmail
                System.Net.NetworkCredential mailAuthentication = new
                System.Net.NetworkCredential("my_Email@gmail.com‏", "my_password");
                //Smtp Mail server of Gmail is "smpt.gmail.com" and it uses port no. 587
                //For different server like yahoo this details changes and you can
                //get it from respective server.
                System.Net.Mail.SmtpClient mailClient = new System.Net.Mail.SmtpClient("smtp.gmail.com", 587);
                //Enable SSL
                mailClient.EnableSsl = true;
                mailClient.UseDefaultCredentials = false;
                mailClient.Credentials = mailAuthentication;
                mailClient.Send(mailMessage);

                lblMsg.Text = "success";
            }
            catch (Exception ex)
            {

                lblMsg.Text = "Error occured while sending your message." + ex.Message;
            }
        }

当到达mailClient.Send（mailMessage）时，它不会陷入低谷，而我得到这个错误：“ SMTP服务器需要安全连接或客户端未通过身份验证。服务器响应为：5.5.1需要身份验证。”

我已经将“允许不太安全的应用程序”切换为“开启”，但对我来说仍然无效。