Sample code for 30+ languages & platforms
.NET Core C#

Send email using SMTP STARTTLS.

Send email using SMTP STARTTLS. With STARTTLS, the SMTP client connects to the SMTP server on port 25 (non-SSL) and then issues a STARTTLS command to convert the connection to a secure TLS channel.

Chilkat .NET Core C# Downloads

.NET Core C#
bool success = false;

// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

// The mailman object is used for sending and receiving email.
Chilkat.MailMan mailman = new Chilkat.MailMan();

// Set the SMTP server.
mailman.SmtpHost = "smtp.mymailserver.com";

mailman.SmtpUsername = "myLogin";
mailman.SmtpPassword = "myPassword";

mailman.StartTLS = true;

// Create a new email object
Chilkat.Email email = new Chilkat.Email();

email.Subject = "This is a test";
email.Body = "This is a test";
email.From = "Chilkat Support <support@chilkatsoft.com>";
success = email.AddTo("Chilkat Admin","admin@chilkatsoft.com");

success = mailman.SendEmail(email);
if (success != true) {
    Debug.WriteLine(mailman.LastErrorText);
    return;
}

success = mailman.CloseSmtpConnection();
if (success != true) {
    Debug.WriteLine("Connection to SMTP server not closed cleanly.");
}

Debug.WriteLine("Mail Sent!");