C#

SMTP GMail Send using App Password

See more GMail SMTP/IMAP/POP Examples

Demonstrates how to authenticate using an app password with GMail for SMTP (port 465 using implicit SSL/TLS). C#

bool success = false;

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

// Starting May 30, 2022, Google will no longer support the use of third-party apps or devices 
// which ask you to sign in to your Google Account using only your username and password.

// Instead of authenticating with your GMail username/password, a GMail user can create an App Password
// and then login using their username/app_password.   It's literally the same, except it allows a GMail
// account owner to isolate passwords to specific applications.

// The Gmail account owner would first need to make sure she has 2-Step Verification setup for her account.
// Note: The 2FA verification is not a factor when authenticating with an app password. The 2FA is required
// to setup app passwords in the Google account console.  See Sign in with App Passwords

// After the GMail account owner has setup his app password, he simply uses the app password instead of his GMail account password.

Chilkat.MailMan mailman = new Chilkat.MailMan();

mailman.SmtpHost = "smtp.gmail.com";

mailman.SmtpUsername = "user@gmail.com";
mailman.SmtpPassword = "srnyyvqajocnsvdp";

mailman.SmtpSsl = true;
mailman.SmtpPort = 465;

success = mailman.SmtpConnect();
if (success == false) {
    Debug.WriteLine(mailman.LastErrorText);
    return;
}

success = mailman.SmtpAuthenticate();
if (success == false) {
    Debug.WriteLine(mailman.LastErrorText);
    return;
}

Debug.WriteLine("SMTP Success!");