Managed C++/CLI - Send email using Hotmail, Outlook.com, Office 365

The following C++/CLI 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.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

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

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.

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 3.1, .NET 5.0, .NET Standard 2.0 and .NET Compact Framework 2.0, 3.5.

File .NET Framework Version
Lib\net20\EASendMail.dll Built with .NET Framework 2.0
It requires .NET Framework 2.0, 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\netcoreapp3.1\EASendMail.dll Built with .NET Core 3.1
It requires .NET Core 3.1 or later version.
Lib\net5.0\EASendMail.dll Built with .NET 5.0
It requires .NET 5.0 or later version.
Lib\net6.0\EASendMail.dll Built with .NET 6.0
It requires .NET 6.0 or later version.
Lib\netstandard2.0\EASendMail.dll Built with .NET Standard 2.0
It requires .NET Standard 2.0 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++/CLI - 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.

#include "stdafx.h"

using namespace System;
using namespace EASendMail;

int main(array<System::String ^> ^args)
{
    try
    {
        SmtpMail ^oMail = gcnew SmtpMail("TryIt");

        // Your Hotmail/Outlook/Office 365 email address
        oMail->From = "liveid@hotmail.com";

        // Set recipient email address, please change it to yours
        oMail->To = gcnew AddressCollection("support@emailarchitect.net");

        // Set email subject
        oMail->Subject = "test email from Managed C++/CLI using hotmail";

        // Set email body
        oMail->TextBody = "this is a test email sent from Managed C++ project with Hotmail";

        // Hotmail SMTP server address
        SmtpServer ^oServer = gcnew 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";

        // use 587 TLS port
        oServer->Port = 587;

        // detect SSL/TLS automatically
        oServer->ConnectType = SmtpConnectType::ConnectSSLAuto;

        Console::WriteLine("start to send email with TLS connection...");

        SmtpClient ^oSmtp = gcnew 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);
    }

    return 0;
}

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

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

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

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

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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