MailMessage mail = new MailMessage();
            SmtpClient SmtpServer = new SmtpClient("smtp.office365.com");
            mail.From = new MailAddress("admin@avantustraining.com");
            mail.Sender = new MailAddress("admin@avantustraining.com");
            mail.To.Add(To);
            mail.Subject = "Test Mail";
            mail.Body = "This is for testing SMTP mail from GMAIL";


            SmtpServer.Port = 587;
            SmtpServer.UseDefaultCredentials = false;
            SmtpServer.DeliveryMethod = SmtpDeliveryMethod.Network;
            SmtpServer.Credentials = new System.Net.NetworkCredential("engsooncheah@avantustraining.com", "Y#98chea");
            //SmtpServer.UseDefaultCredentials = false;
            SmtpServer.EnableSsl = true;

            SmtpServer.Send(mail);

            Label1.Text = "Mail Send";
        }
        catch(Exception ex)
        {
            Label1.Text=ex.ToString();
        }