Hi, I tried to use Lily account to send the mail from google server. The C# code are: SmtpClient smtpClient = new SmtpClient("smtp.gmail.com", 587);smtpClient.Credentials = new System.Net.NetworkCredential("google_account", "google_password");smtpClient.EnableSsl = true;smtpClient.Send(mail); I already check the send mail account set to allowed google Secure Apps setting.These SW implementation work well from my local, but Lily server will show below error: System.Net.Mail.SmtpException: The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.7.0 Authentication Required. Learn more at at System.Net.Mail.MailCommand.CheckResponse(SmtpStatusCode statusCode, String response) at System.Net.Mail.MailCommand.Send(SmtpConnection conn, Byte[] command, MailAddress from, Boolean allowUnicode) at System.Net.Mail.SmtpTransport.SendMail(MailAddress sender, MailAddressCollection recipients, String deliveryNotify, Boolean allowUnicode, SmtpFailedRecipientException& exception) at System.Net.Mail.SmtpClient.Send(MailMessage message) I saw the mail send connection need to smtpClient.EnableSsl.Not sure it is related Lily not allow the SSL connection?Or maybe I need to set other setting on Lily? Could you please help me? Thanks.