Can't send mail with SmtpClient

Question

Can't send mail. Here is my C# source:

  var to = "[email protected]";
  var subject = "test";
  var body = "test mail";
  var message = new MailMessage(from, to, subject, body);
  var client = new SmtpClient { Credentials = new NetworkCredential("[email protected]", "mypassword") };
  client.Send(message);

here is the App.config:

  <system.net>
    <mailSettings>
      <smtp from="[email protected]">
        <network
          host="mail.mycompany.com"
          port="25"
          userName="[email protected]"
          password="mypassword"
        />
      </smtp>
    </mailSettings>
  </system.net>

So far, if the host/port in App.config are wrong an exception is thrown, but not if user/pass are wrong (obvious security reasons). However, I've succeeded to log-in from Microsof Outlook with just the same user/pass as in the source.

The email is not received, nor in Inbox, neither in Junk folder. How can I validate the server-side (considering it's a part of microsoftonline.com)? What am I missing? What am I doing wrong, please?

Answer 1

I am pretty sure that if server rejectects the email for any reason your code would throw an exception. If it is not then that implies that the server is accepting the emails with the supplied user name and password and technically the mails are "sending" sucesfully. However this is no guarantee that anyone will receive any emails. You need to find out what the email server is doing with these emails and why.

Answer 2

The link below has an example of a very simple send email function that can be called from a console application to test. I know this code works, so it could isolate any issue with your code and maybe shed a little more light on where the issue is.

SendEmail() – Create and Send Email Messages in C#

Answer 3

Got an answer from the IT team - it was a configuration/security issue. Solved with IT. Thanks a lot, everyone.