Develop Reference

Go Daddy email SMTP not sending email but no error

I've recently purchased the essentials email package from GoDaddy and I am trying to set up sending email from my website via SMTP. I have the following code set up.
var smtp = new SmtpClient
{
Host = "mycoolwebsite.com.mail.protection.outlook.com",
Port = 25,
DeliveryMethod = SmtpDeliveryMethod.Network,
UseDefaultCredentials = false,
Credentials = new NetworkCredential("info#mycoolwebsite.com", "supersecurepassword")
};
using (var message = new MailMessage("info#mycoolwebsite.com", "myemail#test.com")
{
IsBodyHtml = true,
Subject = subject,
Body = body
})
{
smtp.Send(message);
}
This gets to send and doesn't throw any exceptions, however the email is not sent. I am very confused at why this doesn't work.
Has anyone got any ideas?

This is going to require TLS which means using MailKit's SMTP. You can get it using the NuGet package manager in Visual Studio. Search for MailKit by Jeffrey Stedfast.
Documentation is here as well.
Once you have all the references in place, use the MailKit.Net.Smtp.SmtpClient class:
Set "smtp.office365.com" as your host
Use port 587.
You will need to add this line after creating your smtp instance because you have no OAuth token:
smtp.AuthenticationMechanisms.Remove("XOAUTH2");
That will do what you need.
Here's an example of what the whole thing should look like:
string FromPseudonym = "MySite Support";
string FromAddress = "admin#MySite.com";
var message = new MimeMessage();
message.From.Add(new MailboxAddress(FromPseudonym, FromAddress));
message.To.Add(new MailboxAddress("Recipient Pseudonym", "RecipientAddress#somewhere.com"));
message.Subject = "Testing Email";
var bodyBuilder = new BodyBuilder();
string MsgBody = "Message Body stuff goes here";
bodyBuilder.HtmlBody = MsgBody;
message.Body = bodyBuilder.ToMessageBody();
using (var client = new SmtpClient())
{
client.Connect("smtp.office365.com", 587);
client.AuthenticationMechanisms.Remove("XOAUTH2");
client.Authenticate(FromAddress, "Your super secret password goes here");
client.Send(message);
client.Disconnect(true);
}
You'll need the following namespaces to be included:
using MimeKit;
using MimeKit.Utils;
using MailKit.Net.Smtp;

I've been where you are before. If you are running the app from your dev environment, the emails will not be sent. GoDaddy SMTP is configured so that emails will only be sent when requested from within their environment.
If you push the code to their host and run it, it will work. The most painful thing about this is that everything appears to go smoothly, but the SMTP client just eats the request and leaves you wondering why no email is sent.

Not knowing anything about GoDaddy's API, the only thing I can suggest, is maybe verify that the port is correct. It might require transport layer security, in which case port 25 will be closed.
For example, I think the office365 SMTP server (smtp.office365.com) requires secure SMTP and uses port 587.

Why can't I send e-mail from a C# app when I can send e-mail from a mail client just fine?

I have a task to troubleshoot why a C# app is failing to send automated e-mail messages. I carefully checked the source code, and could find absolutely nothing wrong.
Therefore, I tried to send e-mail from Thunderbird, the e-mail client I normally use. I specified the same SMTP relay, the same UID and password, and everything worked fine.
Trying to isolate the problem, I tried writing a very short C# console app to see what might be going wrong. I wrote the following:
using System.Net;
using System.Net.Mail;
namespace ConsoleApp3
{
class Program
{
static void Main(string[] args)
{
var client = new SmtpClient("my.server.with.ssl", 465);
client.EnableSsl = true;
client.Credentials = new NetworkCredential("uid", "pwd");
var message = new MailMessage("me#example.com", "myemail#mydomain", "Test Message Subject", "Test Message Body");
client.Send(message);
}
}
}
I entered the same credentials that I used in Thunderbird. When I run the above, I get the following error:
Unhandled Exception: System.Net.Mail.SmtpException: Failure sending mail. ---> System.IO.IOException: Unable to read data from the transport connection: net_io_connectionclosed.
How can it be that e-mail is sent just fine from Thunderbird, but the simple programming above fails to work when I try to send an e-mail from a basic C# app?
Edit I tried changing the port number to 587 as suggested in the Question that #stuartd linked to, and in that case, I get an error that says The operation timed out.
Edit I've tried using other e-mail servers and adjusting the settings, but nothing works so far. I've tried connecting to the same SMTP server that I use for my personal e-mail and it shows an error that the connection times out.
Edit I can't say why, but everything seems to be working now in spite of the fact that I didn't change any code. It seems as if something odd happened with my connection.

try using the default constructor and specify the host only.
Also some servers require that the client be authenticated before the server sends e-mail on its behalf. Try changing the value of UseDefaultCredentials
var mail = new MailMessage();
mail.From = new MailAddress("xxx#gmx.net");
mail.To.Add("yyy#gmail.com");
mail.IsBodyHtml = true;
mail.Subject = "subject";
mail.Body = "content";
var client = new SmtpClient();
client.UseDefaultCredentials = false;
client.Host = "mail.gmx.net";
client.EnableSsl = true;
client.Credentials = new NetworkCredential("user", "pass");
client.Send(mail);
if that doesn't help than tell us the server name if its the public one

Try using:
SmtpClient smtpClient = new SmtpClient("mail.mymailhost.com");
smtpClient.Credentials = System.Net.CredentialCache.DefaultNetworkCredentials;

SmtpException when Sending Mail in ASP.NET

I have some code that I am attempting to use to send emails from my ASP.NET MVC 5 website. From what I have read I am doing this the right way and the code is correct
public static Task SendEmailAsync(IEnumerable<string> to,
IEnumerable<string> cc, string body)
{
if (to == null || to.Count() == 0)
return null;
if (String.IsNullOrEmpty(body))
throw new ArgumentNullException("body of the email is empty");
// Send email.
return Task.Factory.StartNew(() =>
{
// Client setup.
using (SmtpClient smtpClient = new SmtpClient("smtp.servername.com", 25)) // Tried 587 too.
{
smtpClient.Credentials = new System.Net.NetworkCredential()
{
UserName = Constants.AdminEmailAddress,
Password = Constants.AdminPwd
};
smtpClient.UseDefaultCredentials = true;
smtpClient.DeliveryMethod = SmtpDeliveryMethod.Network;
smtpClient.EnableSsl = true;
// Mail message.
using (MailMessage mail = new MailMessage())
{
mail.Body = body;
mail.From = new MailAddress(Constants.AdminEmailAddress, "Business Name Here");
foreach (var a in to)
mail.To.Add(new MailAddress(a));
if (cc != null)
foreach (var a in cc)
mail.CC.Add(new MailAddress(a));
smtpClient.Send(mail); // Here I get exception.
}
}
});
}
But on the line marked above I get
System.Net.Mail.SmtpException: Unable to connect to the remote server A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond NNN.NNN.NNN.NNN:MMM
I understand that this is clearly saying that the client cannot connect, but these are the exact same details that I am using to send email from Microsoft Outlook and that works.
Why can't I connect to the mail server using these credentials, what am I missing?
I am aware that I may have to contact the mail service provider and ask for permissions, but this is my first attempt at this and would like some clarification about what to do. I have looked at mandrillapp.com which provides a mail service, is this a good option, can someone advise?
Thank for your time.
Note, I have read
How to send email from Asp.net Mvc-3?
http://www.c-sharpcorner.com/UploadFile/sourabh_mishra1/sending-an-e-mail-using-Asp-Net-mvc/
send email from MVC 4 ASP.NET app
Update
Following the very helpful suggestions by #Dave Zych below I have removed the SmtpException but I now have System.Security.Authentication.AuthenticationException saying "The remote certificate is invalid according to the validation procedure.". So I am in the same boat and still cannot send email.

Don't specify UseDefaultCredentials (or set it to false). That causes it to use the credentials of the currently logged in user, not what you set in the Credentials property.
From MSDN:
Some SMTP servers require that the client be authenticated before the server sends e-mail on its behalf. Set this property to true when this SmtpClient object should, if requested by the server, authenticate using the default credentials of the currently logged on user. For client applications, this is the desired behavior in most scenarios.
...
If the UseDefaultCredentials property is set to false, then the value set in the Credentials property will be used for the credentials when connecting to the server. If the UseDefaultCredentials property is set to false and the Credentials property has not been set, then mail is sent to the server anonymously.

SMTP email client is throwing errors "Timeout" or "requires secure connection" even with correct credential

I was new to SMTP client in C#. So I decided to test it with my credentials. I built an ASP.NET Web forms application that has a Contact Us page on which I am trying to send an email to whoever person fills the form.
I tried sample code after going through this article - https://www.c-sharpcorner.com/UploadFile/87b416/sending-a-simple-email-using-smtpclient-in-C-Sharp/
I have one account in Yahoo so I used its SMTP domain "smtp.mail.yahoo.com" with port number: 465, then my app always threw Timeout exception. So I decided to try with Google's server "smtp.gmail.com" with "587" port and now it raised different exception with message:
The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required
I don't understand what are the prerequisites for working with SMTP on secure servers like Google and Yahoo. Please someone explain.
Also note that I didn't have 2 step verification enabled for my Google account, just to make it clear since some questions on SO have mentioned that this might be the problem.
I also read this question but I am testing directly on my machine - Gmail Error :The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required
In case if it helps, here is the sample code:
try
{
MailMessage m = new MailMessage();
m.From = new MailAddress("dummy123#gmail.com");
m.To.Add(new MailAddress("dummyreceiver123#gmail.com"));
m.Subject = TBSub.Text;
m.Body = TBBody.Text;
m.IsBodyHtml = true;
NetworkCredential nc = new NetworkCredential();
nc.UserName = "dummy123"
nc.Password = "dummy#123";
SmtpClient smtp = new SmtpClient("smtp.gmail.com", 587);
smtp.Credentials = nc;
smtp.EnableSsl = true;
smtp.DeliveryMethod = SmtpDeliveryMethod.Network;
smtp.Send(m);
}
catch (Exception ex)
{
//Log this error
}

I just tested out your code it works fine you just need to modify this section:
nc.UserName = "test"
nc.Password = "password";
This has to be a valid gmail or google app email along with the password for the smtp connection to work properly. I would recommend that you put in your own for testing purposes, and then modify this to have your email as well:
m.From = new MailAddress("yourEmail#gmail.com");
m.To.Add(new MailAddress("yourEmail#gmail.com"));
Just so that you can validate that your message is being passed from your function.

smtp.live.com - mailbox unavailable. The server response was: 5.7.3 requested action aborted; user not authenticated

I have read other answers on the stackoverflow. but none of the solutions work for me.
I'm trying to send email through live.com, but unable to it.
The error message:
mailbox unavailable. The server response was: 5.7.3 requested action aborted;
user not authenticated
The code:
MailMessage mail = new MailMessage();
mail.From = new MailAddress("email#live.com");
mail.To.Add("someone#someone.com");
mail.Subject = "hello";
mail.Body = "awefkljj kawefl";
mail.IsBodyHtml = false;
SmtpClient smtp = new SmtpClient("smtp.live.com", 587);
smtp.EnableSsl = true;
smtp.Credentials = new NetworkCredential("email#live.com", "password");
smtp.Send(mail);
Are you able to send the email by using above code?
It works before, last year, but it is no more working now.
What had been changed?

I ran into an issue where I was unable to send emails using the smtp.live.com SMTP server from certain hosts -- particulary Azure hosts. In my case, the SMTP attempt was from a host that I had never used to sign-in previously, so the attempt was blocked with the 5.7.3 error:
Mailbox unavailable. The server response was: 5.7.3 requested action aborted; user not authenticated
The solution was to browse to the account settings, locate the SMTP request in its recent activity, and select "This was me":

In my case I was using a gmail account but was telling the service otherwise.
I changed:
smtp.Host = "smtp.live.com";
To:
smtp.Host = "smtp.gmail.com";
Which resolved my issue.

This Solved My Problem:
smtpClient.UseDefaultCredentials = false;
smtpClient.Credentials = new NetworkCredential("myaccount#live.com","mypassword");
UseDefaultCredentialsproperty should set to false before setting Credentials

If you have this problem on 2017, and you think you are probaly using an office 365 account, make sure to change the host to "smtp.office365.com". It worked for me.