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Send Email using Hotmail/Live/Outlook/Office 365 in C#

In previous section, I introduced how to send email using Yahoo account. In this section, I will introduce how to send email using Hotmail/Live/Office 365 in C#.

Introduction

Hotmail/Live/Outlook.com SMTP server address is smtp.office365.com. It requires explicit SSL (TLS) connection to do user authentication, and you should use your Hotmail/Live/Outlook.com email address as the user name for ESMTP authentication. For example: your email is myid@hotmail.com, and then the user name should be myid@hotmail.com.

Server Port SSL/TLS
smtp.office365.com 25, 587 TLS

Note

Remarks: All of samples in this section are based on first section: Send email in a simple C# project. To compile and run the following example codes successfully, please click here to learn how to create the test project and add reference of EASendMail to your project.

[C# - Send Email using Hotmail/Live/Outlook.com over Explicit SSL (TLS) on 25 or 587 Port - Example]

The following example codes demonstrate how to send email using Hotmail/Live/Outlook.com in C# over TLS 25 or 587 port.

Note

To get the full sample projects, please refer to Samples section.

using System;
using System.Collections.Generic;
using System.Text;
using EASendMail; //add EASendMail namespace
namespace mysendemail
{
    class Program
    {
        static void Main(string[] args)
        {
            try
            {
                SmtpMail oMail = new SmtpMail("TryIt");

                // Your Hotmail email address
                oMail.From = "liveid@hotmail.com";
                // Set recipient email address
                oMail.To = "support@emailarchitect.net";

                // Set email subject
                oMail.Subject = "test email from hotmail account";
                // Set email body
                oMail.TextBody = "this is a test email sent from c# project with hotmail.";

                // Hotmail SMTP server address
                SmtpServer oServer = new SmtpServer("smtp.office365.com");

                // Hotmail user authentication should use your
                // email address as the user name.
                oServer.User = "liveid@hotmail.com";

                // If you got authentication error, try to create an app password instead of your user password.
                // https://support.microsoft.com/en-us/account-billing/using-app-passwords-with-apps-that-don-t-support-two-step-verification-5896ed9b-4263-e681-128a-a6f2979a7944
                oServer.Password = "your password or app password";

                // Set 587 port, if you want to use 25 port, please change 587 to 25
                oServer.Port = 587;

                // detect SSL/TLS connection automatically
                oServer.ConnectType = SmtpConnectType.ConnectSSLAuto;

                Console.WriteLine("start to send email over SSL...");

                SmtpClient oSmtp = new SmtpClient();
                oSmtp.SendMail(oServer, oMail);

                Console.WriteLine("email was sent successfully!");
            }
            catch (Exception ep)
            {
                Console.WriteLine("failed to send email with the following error:");
                Console.WriteLine(ep.Message);
            }
        }
    }
}

Hotmail SMTP OAUTH

If your account enabled two-factor authentication, you cannot login your account by normal user authentication, you should use SMTP OAUTH or App Password.

Microsoft Live SMTP servers (Hotmail, Oultook personal account) have been extended to support authorization via the industry-standard OAuth 2.0 protocol. Using OAUTH protocol, user can do authentication by Microsoft Web OAuth instead of inputting user and password directly in application.

Microsoft will disable traditional user authentication in the future, switching to Microsoft OAuth (Modern Authentication) is strongly recommended now.

Or you can generate App Passwords and use this app password instead of your user password.

Send Email using Office 365

Office 365 SMTP server uses 587 port and explicit SSL (TLS) connection.

Server Port SSL/TLS
smtp.office365.com 25, 587 (recommended) TLS

App Password and SmtpClientAuthenticationDisabled

If your account enabled two-factor authentication, you cannot login your account by normal user authentication, you should create an App Passwords and use this App Password instead of the user password.

You should also check if authenticated client SMTP submission (SMTP AUTH) is enabled:

Enable or disable authenticated client SMTP submission (SMTP AUTH) in Exchange Online.

[C# - Send Email using Office 365 over Explicit SSL (TLS) on 587 Port - Example]

The following example codes demonstrate how to send email using Office 365 in C# over TLS 587 port.

Note

To get the full sample projects, please refer to Samples section.

using System;
using System.Collections.Generic;
using System.Text;
using EASendMail; //add EASendMail namespace
namespace mysendemail
{
    class Program
    {
        static void Main(string[] args)
        {
            try
            {
                SmtpMail oMail = new SmtpMail("TryIt");

                // Your Offic 365 email address
                oMail.From = "myid@mydomain";
                // Set recipient email address
                oMail.To = "support@emailarchitect.net";

                // Set email subject
                oMail.Subject = "test email from office 365 account";
                // Set email body
                oMail.TextBody = "this is a test email sent from c# project.";

                // Your Office 365 SMTP server address,
                // You should get it from outlook web access.
                SmtpServer oServer = new SmtpServer("smtp.office365.com");

                // user authentication should use your
                // email address as the user name.
                oServer.User = "myid@mydomain";

                // If you got authentication error, try to create an app password instead of your user password.
                // https://support.microsoft.com/en-us/account-billing/using-app-passwords-with-apps-that-don-t-support-two-step-verification-5896ed9b-4263-e681-128a-a6f2979a7944
                oServer.Password = "your password or app password";

                // Set 587 port
                oServer.Port = 587;

                // detect SSL/TLS connection automatically
                oServer.ConnectType = SmtpConnectType.ConnectSSLAuto;

                Console.WriteLine("start to send email over SSL...");

                SmtpClient oSmtp = new SmtpClient();
                oSmtp.SendMail(oServer, oMail);

                Console.WriteLine("email was sent successfully!");
            }
            catch (Exception ep)
            {
                Console.WriteLine("failed to send email with the following error:");
                Console.WriteLine(ep.Message);
            }
        }
    }
}

Office365 SMTP/EWS/Ms Graph API OAUTH

If your account enabled two-factor authentication, you cannot login your account by normal user authentication, you should use SMTP/EWS/Ms Graph API OAUTH or App Password.

Microsoft Office365 SMTP/EWS/Ms Graph API servers have been extended to support authorization via the industry-standard OAuth 2.0 protocol. Using OAUTH protocol, user can do authentication by Microsoft Web OAuth instead of inputting user and password directly in application.

Microsoft will disable traditional user authentication in the future, switching to Microsoft OAuth (Modern Authentication) is strongly recommended now.

Or you can generate App Passwords and use this app password instead of your user password.

Next Section

At next section I will introduce how to send email without specified SMTP server.

Appendix

Comments

If you have any comments or questions about above example codes, please click here to add your comments.

See Also