Validate smtp credentials before sending email on c#
For validation email and password invoke:
var login = "[email protected]";
var password = "testtesttest";
var smtpServer = "smtp.mail.ru";
var smtpPort = 465;
var enableSsl = true;
var isValid = SmtpHelper.ValidateCredentials(login, password, smtpServer, smtpPort, enableSsl);
This lib used in https://b2bfamily.com for validation user credentials.