Gmail 发送错误 (C#)

Question

我正在尝试通过 C# 发送电子邮件，但我一直收到此错误：

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...

可以在此处找到堆栈跟踪：

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

at System.Net.Mail.MailCommand.CheckResponse(SmtpStatusCode statusCode, String response)

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 Repetrel.View.EmailForm.btnSend_Click(Object sender, EventArgs e) in c:15 Hyrel Projects\Repetrel\src\Repetrel\View\EmailForm.cs:line 238

这是我的代码：

            NetworkCredential loginInfo = new NetworkCredential(Properties.Settings.Default.MyEmailAddress, Properties.Settings.Default.MyEmailPassword);
            //System.Net.Mail.SmtpClient smtpClient = new System.Net.Mail.SmtpClient(Properties.Settings.Default.SMTPAddress);
            ////Trace.WriteLine("smtp = " + Properties.Settings.Default.SMTPAddress);
            //smtpClient.Port = 587;
            //smtpClient.EnableSsl = true;
            //smtpClient.DeliveryMethod = SmtpDeliveryMethod.Network;
            ////smtpClient.UseDefaultCredentials = false;
            //smtpClient.Credentials = loginInfo;

            var smtpClient = new SmtpClient
            {
                Host = "smtp.gmail.com",
                Port = 587,
                EnableSsl = true,
                DeliveryMethod = SmtpDeliveryMethod.Network,
                UseDefaultCredentials = true,
                Credentials = loginInfo,
                Timeout = 20000
            };

            //smtpClient.SendAsync(message, "test");
            smtpClient.Send(message);

            //Output to log
            OutputToLog(message);

            //Close Window
            Close();
        }
        catch (Exception ex)
        {
            Trace.WriteLine(ex.ToString());
            MessageBox.Show("An error occurred.  Please see the trace log for more information.");
        }

我已经尝试了之前帖子中提到的所有方法（有很多），但似乎没有任何效果。我尝试过使用和不使用默认凭据并将标志设置为 false/true。似乎没有任何效果。谁能给我指出正确的方向？

提前致谢！

Answer 1

也许 UseDefaultCredentials = false, 而不是？

编辑： 这似乎类似于一个较早的 Whosebug 问题：SmtpClient with Gmail

Answer 2

显然 GMAIL 阻止我的电子邮件地址使用不太安全的设备。您可以在以下位置关闭阻止：https://www.google.com/settings/security/lesssecureapps.

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