I have a website with an ASP.NET MVC backend running .NET 3.5. On this website, there is a script that sends emails using gmail as the mail service. The script runs and sends mail fine locally on my dev machine, but as soon as I upload it to the live server it fails. The only error message it is giving me at the moment is (since I told it to as you will see further down):

The transport failed to connect to the server.

Here is the code for the mailer script:

using System.Net.Mail;
using System.Web.Mail;
using MailMessage = System.Web.Mail.MailMessage;

namespace MySite.Helpers
{
    public class GmailHelper
    {
        private readonly int _port = 465;
        private readonly string _accountName;
        private readonly string _password;

        public GmailHelper(string accountName, string password)
        {
            _accountName = accountName;
            _password = password;
        }
        public GmailHelper(string accountName, string password, int port)
        {
            _acc开发者_开发百科ountName = accountName;
            _password = password;
            _port = port;
        }
        public void Send(string from, string to, string subject, string body, bool isHtml)
        {
            Send(from, to, subject, body, isHtml, null);
        }

        public void Send(string from, string to, string subject, string body, bool isHtml, string[] attachments)
        {

            var mailMessage = new MailMessage

                                                          {
                                                              From = from,
                                                              To = to,
                                                              Subject = subject,
                                                              Body = body,
                                                              BodyFormat = isHtml ? MailFormat.Html : MailFormat.Text
                                                          };


            // Add attachments
            if (attachments != null)
            {
                foreach (var t in attachments)
                {
                    mailMessage.Attachments.Add(new Attachment(t));
                }
            }

            //  Authenticate
            mailMessage.Fields.Add("http://schemas.microsoft.com/cdo/configuration/smtpauthenticate", 1);
            // Username for gmail - email@domain.com for email for Google Apps
            mailMessage.Fields.Add("http://schemas.microsoft.com/cdo/configuration/sendusername", _accountName);
            // Password for gmail account
            mailMessage.Fields.Add("http://schemas.microsoft.com/cdo/configuration/sendpassword", _password);
            // Google says to use 465 or 587.  I don't get an answer on 587 and 465 works - YMMV
            mailMessage.Fields.Add("http://schemas.microsoft.com/cdo/configuration/smtpserverport", _port.ToString());
            // STARTTLS 
            mailMessage.Fields.Add("http://schemas.microsoft.com/cdo/configuration/smtpusessl", true);

            // assign outgoing gmail server
            SmtpMail.SmtpServer = "smtp.gmail.com";
            SmtpMail.Send(mailMessage);
        }
    }
}

And here is how it is called:

[HttpPost]
public ActionResult Employment(EmploymentModel model, FormCollection collection)
{
    if (!ModelState.IsValid)
        return View(model);

    var results = new EmploymentViewModel();
    try
    {

        results.Position = model.Position;
        results.FirstName = model.FirstName;
        results.LastName = model.LastName;
        results.ContactPhone = model.ContactPhone;
        results.OtherPhone = model.OtherPhone;
        results.Address = model.Address;
        results.Email = model.Email;
        results.HsDiploma = model.HsDiploma.ToString();
        results.CollegeYears = model.CollegeYears;
        results.Skills = model.Skills;
        results.Employment = model.Employment;
        results.DateSent = DateTime.Now.ToString("MM/dd/yyyy HH:mm:ss");

        var gmail = new GmailHelper("noreply@mysite.com", "[*removed*]");

        var fromAddress = new MailAddress("noreply@mysite.com", "MySite");
        var toAddress = new MailAddress("applications@mysite.com", "MySite Employment");
        var subject = string.Format("Employment Application for {0} {1}", model.FirstName, model.LastName);

        gmail.Send(fromAddress.Address, toAddress.Address, subject, EmployMailBody(results), false);
    }
    catch (Exception ex)
    {
        results.Sent = false;
        results.Title = "Oops, our mail drone seems to have malfunctioned!";
        results.Message = string.Format("We appologize, {0} {1}, but our email system has encountered an error and your email was not sent.</p>",
                results.FirstName, results.LastName);
        results.Message += Environment.NewLine + "<p>Please try your request later, or fax your résumé to our Corporate office.";
        results.Message += Environment.NewLine + JQueryHelpers.GenerateErrorField(ex.Message);

        return View("EmploymentSubmit", results);
    }
    results.Sent = true;
    results.Title = "Thank you for your submission!";
    results.Message = string.Format("Thank you for your interest in joining our team, {0} {1}!</p>", results.FirstName, results.LastName);
    results.Message += Environment.NewLine + "<p>We have successfully recieved your information and will contact you shortly at the number your have provided.";

    return View("EmploymentSubmit", results);
}

I am 99% positive that it was functional before when it was up on the site, but I could be mistaken as it has been a month or so since I have had to update the site.

Are there some additional steps I can take to debug this "better" to track down the underlying issue, or did I botch up my code somewhere accidentally?

Thanks!

EDIT1

So I updated the class to use strictly System.Net.Mail. I successfully sent a message from my dev machine. When I uploaded the site to my server, however, I got a new error message:

Request for the permission of type 'System.Net.Mail.SmtpPermission, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' failed.

This site is hosted through godaddy.com, and some after searching around it seems godaddy only allows relaying through their smtp server. It looks like I'll have to change hosting providers to get this working properly.

Thanks!

EDIT2

The reason I moved to gmail from godaddy is originally when I had this script up the email would take anywhere from 15 to 45 minutes to arrive at the destination box. This could have been the deprecated code I was using before, but either way it is now being dispatched and arriving within seconds, as it should be. Here is my GoDaddy helper class, in case it will help someone:

public class GoDaddyHelperNet
{
    private readonly int _port = 25;
    private readonly MailAddress _accountName;
    private readonly string _password;
    private readonly string _host = "relay-hosting.secureserver.net";

    public GoDaddyHelperNet(MailAddress accountName, string password)
    {
        _accountName = accountName;
        _password = password;
    }
    public GoDaddyHelperNet(MailAddress accountName, string password, int port)
    {
        _accountName = accountName;
        _password = password;
        _port = port;
    }
    public GoDaddyHelperNet(MailAddress accountName, string password, int port, string host)
    {
        _accountName = accountName;
        _password = password;
        _port = port;
        _host = host;
    }
    public void Send(MailAddress to, string subject, string body, bool isHtml)
    {
        Send(_accountName, to, subject, body, isHtml);
    }

    public void Send(MailAddress from, MailAddress to, string subject, string body, bool isHtml)
    {
        var smtp = new SmtpClient
                       {
                           Host = _host,
                           Port = _port,
                           EnableSsl = false,
                           DeliveryMethod = SmtpDeliveryMethod.Network,
                           UseDefaultCredentials = false,
                           Credentials = new NetworkCredential(from.Address, _password),
                           Timeout = 15000
                       };

        using (var message = new System.Net.Mail.MailMessage(from.Address, to.Address)
                     {
                         Subject = subject,
                         Body = body,
                     })

            smtp.Send(message);
    }
}

---

there is probably a firewall rule or other network device blocking you. verify that you can telnet to the gmail server from your web server and can send an email.

http://www.wikihow.com/Send-Email-Using-Telnet

if you can't you probably have to talk to your network admin. i have email problems like this on about half of my clients web servers.

---

Gmail has got lots of restrictions on SMTP relay. No more than 100 total recipients per day, IIRC. Limits on recipients per message as well. Limits on message/attachment size. If you exceed the limits or Gmail has decided that you look like a spam artiste, their SMTP server may well refuse the connection for a day or so.