Can't auth to Gmail smtp via MailMessage & smtpClient

Question

I cannot figure out for the life of my why this isn\'t working

SmtpClient smtp = new SmtpClient
{
    Host = \"smtp.gmail.com\",
    Port = 587,
    UseDefau         


        

Answer 1

Very simple just follow this for C# WPF Application:

       private void SendByGmail(string subject, string body, string recepientEmail, string MailMsgFrom, string MailMsgPass)
        {
            using (MailMessage mailMessage = new MailMessage())
            {
                mailMessage.From = new MailAddress(MailMsgFrom);
                mailMessage.Subject = subject;
                mailMessage.Body = body;
                mailMessage.IsBodyHtml = true;
                mailMessage.To.Add(new MailAddress(recepientEmail));
                mailMessage.Priority = System.Net.Mail.MailPriority.High;
                SmtpClient smtp = new SmtpClient();
                smtp.Host = "smtp.gmail.com";
                smtp.EnableSsl = true;
                smtp.Timeout = 200000;
                System.Net.NetworkCredential NetworkCred = new System.Net.NetworkCredential();
                NetworkCred.UserName = MailMsgFrom;
                NetworkCred.Password = MailMsgPass;
                smtp.UseDefaultCredentials = true;
                smtp.Credentials = NetworkCred;
                smtp.Port = 587;
                smtp.Send(mailMessage);

            }
        }

After that you should get like this Error

smtpException   {"The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required. Learn more at"}   System.Net.Mail.SmtpException

To Solve this problem, at first login your email account to your google account in web browser. Then just follow this link Google Account Activity. Then you'll get recent Devices & activity by your account. If show block your current activity from your current device. Just Unblock this. Then try again to send email.
Thanks