“The SMTP host was not specified.” - but it is specified?

问题

I'm slightly baffled here - I'm receiving the following error:

The SMTP host was not specified.

Even though my code appears to be correct (from what I can see).

I am able to do it manually by including all the details inside of the controller, e.g.

SmtpClient smtpClient = new SmtpClient("smtp.gmail.com");
smtpClient.Port = 587;
... etc

But I shouldn't have to do this, as I want to use the details inside mailSettings (Making it re-usable for various different controllers).

mailSettings in my Web.Config file:

<system.net>
   <mailSettings>
     <smtp from="example@gmail.com" deliveryMethod="Network" >
       <network host="smtp.gmail.com" defaultCredentials="true" 
                port="587" enableSsl="true" userName="example@gmail.com"
                password="example"/>
     </smtp>
   </mailSettings>
</system.net>

My Controller action:

 [HttpPost]
 public ActionResult SubmitFeature(FormData formData)
 {
     SmtpClient smtpClient = new SmtpClient();

     MailMessage mail = new MailMessage();
     mail.To.Add(new MailAddress("example@gmail.com"));
     mail.Body = "Test";

     smtpClient.Send(mail);

     return View("Example");
 }

Is there anything I'm missing which may be causing this? I haven't messed around with any other settings in Web.Config, they are as is when setting up a new MVC5 project.

回答1:

In a clean MVC project, I am unable to replicate your issue. Following the ScottGu blog post here, I was able to get a gmail sent email without issue (VS 2013, .NET 4.5.1, MVC 5). Note the the <system.net> element is a top level element and not nested inside of AppSettings or <system.web>.

Important

There are a few web.config files in your solution, ensure that the mailSettings is inserted into the root level web.config (and not the one located in the Views folder)

Web.Config

<configuration>
  <system.net>
    <mailSettings>
      <smtp from="myEmail@gmail.com">
        <network host="smtp.gmail.com" 
                 port="587" 
                 enableSsl="true" 
                 userName="myEmail@gmail.com" 
                 password="SuperSecretPwd" 
                 defaultCredentials="false" /> <!--This must be false on Gmail-->
      </smtp>
    </mailSettings>
  </system.net>
</configuration>

Controller

var smtpClient = new SmtpClient();
var msg = new MailMessage();
msg.To.Add("MyOtherAddress@yahoo.com");
msg.Subject = "Test";
msg.Body = "This is just a test email";
smtpClient.Send(msg);

It is unclear if some of the extra attributes you have included are causing issues (thought they shouldn't) such as delivery method. Also, is there a setting for allowing SMTP access or is that just for IMAP/POP delivery?

If you can test and are successful in a clean project, then this would point to either a web.config transformation problem or some other setting(s) in your project overriding the web.config settings that you have in place.

回答2:

The solution was mentioned in the Chat, but never edited into the answer above.

Make sure that you make these settings in the web.config of the Root Level and not in the Views folder.

@Tommy: ...this looks like the web.config from your Views folder and not the web.config at the root of the application

来源：https://stackoverflow.com/questions/21219580/the-smtp-host-was-not-specified-but-it-is-specified