Unable to send email using C# code

Unable to send email using C# code

Hello Everyone , 

I am trying to send email using my Zoho email but its throwing exception. Below is my code in c# and error details: 

                 SmtpClient smtpClient = new SmtpClient();
                smtpClient.Host = "smtp.zoho.com";
                smtpClient.Port = 465;
                smtpClient.EnableSsl = true;
                smtpClient.DeliveryMethod = SmtpDeliveryMethod.Network;
                smtpClient.UseDefaultCredentials = true;
                smtpClient.Credentials = new System.Net.NetworkCredential(" XXXXXX@XXXX.sg", "******");

                MailMessage message = new MailMessage();


                message.From = new MailAddress("" XXXXXX@XXXX.sg"");
                message.To.Add(" myEmail@gmail.com");
                message.Subject = "Test Subject";
                message.IsBodyHtml = true;
                message.Body = "Message body...";

                smtpClient.Send(message);





The error which we are getting :  
-------------------------------
                The operation has timed out.


I am not sure how to make it happen. I have checked and can send email using zoho site which means email is working well. 

any help would be greatly appreciated

Thanks