System.net.mail.smtpstatuscode.mustissuestarttlsfirst
A specific error!
System.Net.Mail.SmtpStatusCode.MustIssueStartTlsFirst
is an error code returned by the SMTP server when it requires the client to issue a STARTTLS command before sending any other commands.
Here's what's happening:
- Your application is trying to send an email using the
System.Net.Mail
namespace. - The SMTP server (e.g., Gmail, Outlook, etc.) requires the client to use TLS (Transport Layer Security) encryption to send emails.
- The SMTP server is responding with a
MustIssueStartTlsFirst
error code, indicating that the client must issue a STARTTLS command before sending any other commands.
To resolve this issue, you need to modify your code to issue a STARTTLS command before sending the email. Here's an example in C#:
using System.Net.Mail;
using System.Net.Security;
// Create an SMTP client
SmtpClient client = new SmtpClient();
// Set the SMTP server and port
client.Host = "smtp.gmail.com";
client.Port = 587;
// Set the encryption method
client.EnableSsl = true;
// Set the username and password
client.Credentials = new NetworkCredential("[email protected]", "your_password");
// Create a mail message
MailMessage message = new MailMessage("[email protected]", "[email protected]", "Subject", "Body");
// Issue the STARTTLS command
client.GetResponse();
// Send the email
client.Send(message);
In this example, we set EnableSsl
to true
to enable TLS encryption. Then, we issue the STARTTLS command using GetResponse()
before sending the email.
If you're using a different SMTP client library or framework, you may need to consult its documentation for specific instructions on how to issue the STARTTLS command.