C# E-mail Client Mails Not Received

[cnixuser]

Hi, I am trying to write an application that will e-mail sales data reports once per day. I have largely succeeded in creating the application and I am able to e-mail my reports to some e-mail addresses such as gmail ones ;however, when attempting to send e-mails to addresses on my companies internal server the e-mails never arrive. I was wondering if anyone knew what could allow gmail addresses to receive e-mails from my application, but not allow other servers to receive mail from my application, below is the portion of code doing the e-mailing:

        public string SendEmail()
        {
            try
            {
                using (System.Net.Mail.MailMessage message = new System.Net.Mail.MailMessage(EmailFrom, EmailTo))
                {
                    message.Subject = ConfigurationManager.AppSettings["emailSubject"].ToString();
                    message.Body = ConfigurationManager.AppSettings["emailMainBody"].ToString() + "\n\nSent On:\n" + DateTime.Now.ToString() + "\n" + SerialPortCommands.RemoveControlCharacterPairs(SerialPortCommands.Asciireport);
                    //System.Net.Mail.SmtpClient Client = new System.Net.Mail.SmtpClient("localhost");
                    System.Net.Mail.SmtpClient Client = new System.Net.Mail.SmtpClient("127.0.0.1");
                    Client.DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.PickupDirectoryFromIis;
                    Client.Send(message);
                    Thread.Sleep(2000);
                }
                return null;
            }
            catch (Exception ex)
            {
                Log.WriteToLog(ex);
                return "Error Code: email-1";
                Application.Restart();
            }
        }

And here are the relevant portions from my App.Config file:

<add key="ToAddress" value="[e-mail]"/>
    <add key="FromAddress" value="[e-mail]"/>
    <add key="emailSubject" value="==DEX Collector Message== Your Dex Report Has Been Sent"/>
    <add key="emailMainBody" value="Vending Machine DEX Data"/>
    <add key="MessageSendTime" value="1:17:00 PM"/>

any help would be greatly appreciated, as I am quite stumped :)

[cnixuser]

Hmmm no. It had actually not occured to me that you could be using localhost to send the emails. Will the final product be run in the same manor?

The crenedtials supplied are for the server you are sending mail from. so if you are sending mail from a localhost, I now understand your confusion about what credentials to send.
That being said there are a number of other things in the SMTP protocol that could cause your emails to be rejected. It's possible that godaddy implents the part of the protocol that says there needs to be a valid MX record for the address that is SENDING the messages.
i.e. it needs to be able to go -> somename@somedo main.com....che cking the lookup for somedomain.com
They may also go the next step which would be reverse validation and attempt to verify that someuser is a valid username in somedomain.com

and it could also be none of those and something else entirely.
Your best bet might be to get in touch with whoever handles your email and see if they can find anything in the logs about why your messages are rejected

client.UseDefau ltCredentials = true;
would send my local host's Credentials correct?

[Plater]

client.UseDefau ltCredentials = true;
would send my local host's Credentials correct?

Mmm I think it actually looks in either machine.config or web.config (depending on application type) for them. Unsure what it will send if cannot find them.

[cnixuser]

Mmm I think it actually looks in either machine.config or web.config (depending on application type) for them. Unsure what it will send if cannot find them.

I have another question related to this ;however, at this point should I just go ahead and start a new thread?

[Curtis Rutland]

If it isn't directly related, yes.

Go ahead and post it. We can merge/split it if we need to.

[joedeene]

Well technically no, because I built my own SMTPClient as I disliked the built in one.
But yes, I *DO* send the authentication information to the mail server, my mail server won't send emails out unless you are a valid user.

hey plater, you said you built your own smtpclient class, that has to be awesome, how would you come across doing that? did you implement any of it with the webclient class? just curious

[Plater]

I did it with Sockets and the RFCs for the SMTP specs

[joedeene]

I did it with Sockets and the RFCs for the SMTP specs

what are 'RFCs'? i typed it in google with .net nothing relevant came up

[Plater]

RFCs are Request For Comments. They are used to define internet standards. They are not related to .NET