C# - Send Email using Hotmail, Outlook.com, Office 365

The following c# example codes demonstrate how to send email using Hotmail, Outlook.com and Office 365 SMTP servers.

Hotmail, Outlook.com SMTP Server

Hotmail/Live/Outlook.com SMTP server address is smtp.live.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.live.com 25, 587 TLS

Office 365 SMTP Server

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

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

Installation

Before you can use the following codes, please download EASendMail SMTP Component and install it on your machine at first. Full sample proejcts are included in this installer.

Install from NuGet

You can also install the run-time assembly by NuGet. Run the following command in the NuGet Package Manager Console:

Install-Package EASendMail

Note

If you install it by NuGet, no sample projects are installed, only .NET assembly is installed.

Add Reference

To use EASendMail SMTP Component in your project, the first step is Add reference of EASendMail to your project. Please create or open your project with Visual Studio, then go to menu -> Project -> Add Reference -> .NET -> Browse..., and select Installation Path\Lib\net[version]\EASendMail.dll from your disk, click Open -> OK, the reference of EASendMail will be added to your project, and you can start to use it to send email in your project.

add reference in c#/vb.net/c++/cli/clr

.NET Assembly

Because EASendMail has separate builds for .Net Framework, please refer to the following table and choose the correct dll.

Separate builds of run-time assembly for .NET Framework 1.1, 2.0, 3.5, 4.0, 4.5, 4.6.1, .NET Core 2.1 and .NET Compact Framework 2.0, 3.5.

File .NET Framework Version
Lib\net11\EASendMail.dll Built with .NET Framework 1.1
It requires .NET Framework 1.1, 2.0, 3.5 or later version.
Lib\net20\EASendMail.dll Built with .NET Framework 2.0
It requires .NET Framework 2.0, 3.5 or later version.
Lib\net35\EASendMail.dll Built with .NET Framework 3.5
It requires .NET Framework 3.5 or later version.
Lib\net40\EASendMail.dll Built with .NET Framework 4.0
It requires .NET Framework 4.0 or later version.
Lib\net45\EASendMail.dll Built with .NET Framework 4.5
It requires .NET Framework 4.5 or later version.
Lib\net461\EASendMail.dll Built with .NET Framework 4.6.1
It requires .NET Framework 4.6.1 or later version.
Lib\netcoreapp2.1\EASendMail.dll Built with .NET Core 2.1
It requires .NET Core 2.1 or later version.
Lib\net20-cf\EASendMail.dll Built with .NET Compact Framework 2.0
It requires .NET Compact Framework 2.0, 3.5 or later version.
Lib\net35-cf\EASendMail.dll Built with .NET Compact Framework 3.5
It requires .NET Compact Framework 3.5 or later version.

C# - Send Email using Hotmail, Outlook.com, Office 365 - Example

The following example codes demonstrate sending email using Hotmail, Outlook, Office365 SMTP server. In order to run it correctly, please change SMTP server, user, password, sender, recipient value to yours.

Note

To get full sample projects, please download and install EASendMail on your machine.

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 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, outlook, office 365 account";

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

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

                // If your account is office 365, please change to Office 365 SMTP server
                // SmtpServer oServer = new SmtpServer("smtp.office365.com");

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

                // use 587 TLS port
                oServer.Port = 587;

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

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

                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

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. This way is more secure, but a little bit complex.

Send Email from Hotmail/Outlook/Live using User Interaction OAuth

Office365 EWS OAUTH

Microsoft Office365 EWS 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. This way is more secure, but a little bit complex.

TLS 1.2 Protocol

TLS is the successor of SSL, more and more SMTP servers require TLS 1.2 encryption now.

If your operating system is Windows XP/Vista/Windows 7/Windows 2003/2008/2008 R2/2012/2012 R2, you need to enable TLS 1.2 protocol in your operating system like this:

Enable TLS 1.2 on Windows XP/Vista/7/10/Windows 2008/2008 R2/2012

Appendix

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