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


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


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 EASendMail{version}.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 and .Net Compact Framework 2.0, 3.5.

File .NET Framework Version
EASendMail.dll Built with .NET Framework 1.1
It requires .NET Framework 1.1, 2.0, 3.5 or later version.
EASendMail20.dll Built with .NET Framework 2.0
It requires .NET Framework 2.0, 3.5 or later version.
EASendMail35.dll Built with .NET Framework 3.5
It requires .NET Framework 3.5 or later version.
EASendMaill40.dll Built with .NET Framework 4.0
It requires .NET Framework 4.0 or later version.
EASendMaill45.dll Built with .NET Framework 4.5
It requires .NET Framework 4.5 or later version.
EASendMailCF20.dll Built with .NET Compact Framework 2.0
It requires .NET Compact Framework 2.0, 3.5 or later version.
EASendMailCF35.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.


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)
            SmtpMail oMail = new SmtpMail("TryIt");
            SmtpClient oSmtp = new SmtpClient();

            // 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...");
                oSmtp.SendMail(oServer, oMail);
                Console.WriteLine("email was sent successfully!");
            catch (Exception ep)
                Console.WriteLine("failed to send email with the following error:");



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