The SMTP server requires a secure connection or the client was not authenticated
Posted by zeemalik on February 18, 2009
Problem: The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.7.0 Must issue a STARTTLS command first. c25sm1228430ika.11
Solution:
Public Shared Sub SendEmail()
Dim Message As New Net.Mail.MailMessage()
Dim FromEmail As New Net.Mail.MailAddress(“From Email Address”)
Message.From = FromEmail
Message.To.Add(“To Email Address”)
Message.Subject = “Subject of the Email”
Message.Body = “Body of the Email”
‘Message.SubjectEncoding = System.Text.Encoding.UTF8
‘Message.BodyEncoding = System.Text.Encoding.UTF8
‘Message.IsBodyHtml = False
‘Message.Priority = Net.Mail.MailPriority.High
Dim SmtpClient As New Net.Mail.SmtpClient(“smtp.YourEmailServer.com”, PortNo eg: 587 for gmail )
SmtpClient.EnableSsl = True
’smtp.DeliveryMethod = Net.Mail.SmtpDeliveryMethod.Network
’smtp.UseDefaultCredentials = False
SmtpClient.Credentials = New Net.NetworkCredential(“YourEmailAddress”, “YourEmailPassword”)
SmtpClient.Send(Message)
End Sub
Note: An important point to note is that you have to set the EnableSSl to True before you set the NetWork Credentials of your SMTP client.
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dotnetolympians said
Thanks for sharing!
rabi said
i m a .net developer.
i’m trying to send mail from asp application.
i’m using visual studio 2008 And C#.
I’m getting error “The SMTP server requires a secure connection or the client was not authenticated. The server response was: authentication required”
My code is
MailMessage mail = new MailMessage();
mail.To.Add(TextTo.Text);
mail.From = new MailAddress(TextFrom.Text);
mail.Subject = TextSbj.Text;
mail.Body = TextBody.Text;
SmtpClient smtp = new SmtpClient();
smtp.Host = “in.smtp.mail.yahoo.com “;
smtp.Port = 587;
//smtp.EnableSsl = true;
smtp.UseDefaultCredentials = false;
smtp.Credentials = new System.Net.NetworkCredential(“username”, “password”);
smtp.DeliveryMethod = SmtpDeliveryMethod.Network;
smtp.Send(mail);
anyone help
thanx