VB.NET/ASP.NET/ASP MVC - Send Email using Microsoft OAuth 2.0 (Modern Authentication) from Hotmail/Outlook Account

You can send email using traditional user/password SMTP authentication from personal Hotmail/Outlook account.

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


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 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.

Create your application in Azure Portal

To use Microsoft/Office365/Live OAuth (Modern Authentication) in your application, you must create a application in https://portal.azure.com.

  • Sign in to the Azure portal using either a work or school account or a personal Microsoft account.

  • If your account gives you access to more than one tenant, select your account in the top right corner, and set your portal session to the Azure AD tenant that you want.

  • In the left-hand navigation pane, select the Azure Active Directory service, and then select App registrations -> New registration.

    azure portal new app registration
  • When the Register an application page appears, enter your application’s registration information:

    azure portal application registration
    • Name - Enter a meaningful application name that will be displayed to users of the app.
    • Supported account types - Select which accounts you would like your application to support. Because we need to support all Office 365 and LIVE SDK (hotmail, outlook personal account) select Accounts "in any organizational directory and personal Microsoft accounts".
  • Redirect URI (optional)

    Select the type of app you’re building, Web or Public client (mobile & desktop), and then enter the redirect URI (or reply URL) for your application.

    For web applications, provide the base URL of your app. For example, http://localhost:31544 might be the URL for a web app running on your local machine. Users would use this URL to sign in to a web client application.

    For public client applications, provide the URI used by Azure AD to return token responses. Enter a value specific to your application, such as myapp://auth.

  • Client Id/secrets

    After you registered your application, Azure AD assigns a unique application (client) ID to your app, and you’re taken to your application’s Overview page. click "Certificates and secrets" -> "client secrets" and add a new client secret.


Please store "client secret" by yourself, because it is hidden when you view it at next time.

API Permission

  • Click "API Permission" -> "Add a permission" -> "Exchange" -> "Delegated Permission" -> "Check EWS.AccessAsUser.All"
  • "Add a permission" -> "Microsoft Graph" -> "Delegated Permission" -> "User.Read", "email", "offline_access", "openid", "profile", SMTP.Send, IMAP.AccessAsUser.All, POP.AccessAsUser.All.
azure application api permission


  • Click "Authentication"

    • Implicit grant: check "Access tokens" and "ID tokens";
    • Redirect URI: input the url to get authorization code, for native desktop application, you don’t have to add redirect uri.
  • Mobile and desktop applications -> Redirect Uri, please check or add the following URI.



    • https://login.live.com/oauth20_desktop.srf is used for Live SDK, is used for local Http Listener.
  • Supported account types:

    Select Accounts in any organizational directory (Any Azure AD directory - Multitenant) and personal Microsoft accounts (e.g. Skype, Xbox)

  • Advanced settings:

    Set both "Live SDK Support" and "Treat application as a public client" to "Yes".

azure application Authentication Overview

Above client id and client secret support both "Office365 + SMTP/EWS" and "Live (hotmail, outlook personal account) + SMTP",

Use client id and client secret to request access token

You can use client id and client secret to get the user email address and access token like this:

  • Your application uses a web browser/browser control to open Microsoft OAUTH URL;
  • User inputs user and password in Microsoft Web Authentication Page, and then Microsoft returns access token back to your application;
  • Your application uses access token to access Hotmail/Outlook/Live SMTP server.
  • You can find full example codes in EASendMail Installation Path\Samples_{Programming language/Developer Tool}\Oauth project.


You should create your client id and client secret, do not use the client id from example codes in production environment, it is used for test purpose. If you got "This app isn't verified" information, please click "Advanced" -> Go to ... for test.

VB.NET - Send Email Using Microsoft OAuth + Hotmail/Outlook/Live SMTP server

Here is a console application which demonstrates how to use Microsoft OAuth to do user authentication and send email.


This sample cannot handle the event of Web Browser is closed by user manually before authentication is completed. You can refer to the better sample project which uses Web Browser Control in EASendMail installation path.

Imports System
Imports System.IO
Imports System.Net
Imports System.Net.Sockets
Imports System.Threading.Tasks
Imports System.Text
Imports System.Runtime.InteropServices
Imports EASendMail

Module ModuleMsOauthHotmail
    Sub Main(ByVal args As String())
        Console.WriteLine("  Sign in with Microsoft OAuth                                       ")
        Console.WriteLine("   If you got ""This app isn't verified"" information in Web Browser, ")
        Console.WriteLine("   click ""Advanced"" -> Go to ... to continue test.")
        Console.WriteLine("Press any key to sign in...")

            Dim p As MsLiveOauth = New MsLiveOauth()
        Catch ep As Exception
        End Try

    End Sub

    Public Class MsLiveOauth
        Private Sub SendMailWithXOAUTH2(ByVal userEmail As String, ByVal accessToken As String)
            ' Hotmail/Outlook/Live SMTP server address
            Dim oServer As SmtpServer = New SmtpServer("smtp.live.com")
            ' enable SSL connection
            oServer.ConnectType = SmtpConnectType.ConnectSSLAuto
            ' Using 587 port, you can also use 465 port
            oServer.Port = 587

            ' use SMTP OAUTH 2.0 authentication
            oServer.AuthType = SmtpAuthType.XOAUTH2
            ' set user authentication
            oServer.User = userEmail
            ' use access token as password
            oServer.Password = accessToken

            Dim oMail As SmtpMail = New SmtpMail("TryIt")

            ' Your email address
            oMail.From = userEmail

            ' Please change recipient address to yours for test
            oMail.[To] = "support@emailarchitect.net"
            oMail.Subject = "test email from Hotmail account with OAUTH 2"
            oMail.TextBody = "this is a test email sent from VB.NET project with Hotmail."

            Console.WriteLine("start to send email using OAUTH 2.0 ...")

            Dim oSmtp As SmtpClient = New SmtpClient()
            oSmtp.SendMail(oServer, oMail)

            Console.WriteLine("The email has been submitted to server successfully!")
        End Sub

        ' client configuration
        ' You should create your client id And client secret,
        ' do Not use the following client id in production environment, it Is used for test purpose only.
        Const clientID As String = "eccbabb2-3377-4265-85c1-ea2fb515f075"
        Const clientSecret As String = "QaR_RR:-5WqTY[nni9pdBr9xVybqrAu4"
        Const scope As String = "wl.offline_access%20wl.signin%20wl.imap%20wl.emails%20email%20openid"
        Const authUri As String = "https://login.microsoftonline.com/common/oauth2/v2.0/authorize"
        Const tokenUri As String = "https://login.microsoftonline.com/common/oauth2/v2.0/token"

        Private Shared Function GetRandomUnusedPort() As Integer
            Dim listener = New TcpListener(IPAddress.Loopback, 0)
            Dim port = (CType(listener.LocalEndpoint, IPEndPoint)).Port
            Return port
        End Function

        Public Async Sub DoOauthAndSendEmail()
            ' Creates a redirect URI using an available port on the loopback address.
            Dim redirectUri As String = String.Format("{0}/", GetRandomUnusedPort())
            Console.WriteLine("redirect URI: " & redirectUri)

            ' Creates an HttpListener to listen for requests on that redirect URI.
            Dim http = New HttpListener()
            Console.WriteLine("Listening ...")

            ' Creates the OAuth 2.0 authorization request.
            Dim authorizationRequest = String.Format("{0}?response_type=code&scope={1}&redirect_uri={2}&client_id={3}&prompt=login",

            ' Opens request in the browser

            ' Waits for the OAuth authorization response.
            Dim context = Await http.GetContextAsync()

            ' Brings the Console to Focus.

            ' Sends an HTTP response to the browser.
            Dim response = context.Response
            Dim responseString As String = String.Format("<html><head></head><body>Please return to the app and close current window.</body></html>")
            Dim buffer = Encoding.UTF8.GetBytes(responseString)
            response.ContentLength64 = buffer.Length
            Dim responseOutput = response.OutputStream
            Dim responseTask As Task = responseOutput.
                WriteAsync(buffer, 0, buffer.Length).
                                Console.WriteLine("HTTP server stopped.")
                            End Sub)

            ' Checks for errors.
            If context.Request.QueryString.[Get]("error") IsNot Nothing Then
                Console.WriteLine(String.Format("OAuth authorization error: {0}.", context.Request.QueryString.[Get]("error")))
            End If

            If context.Request.QueryString.[Get]("code") Is Nothing Then
                Console.WriteLine("Malformed authorization response. " & context.Request.RawUrl)
            End If

            ' extracts the authorization code
            Dim code = context.Request.QueryString.[Get]("code")
            Console.WriteLine("Authorization code: " & code)

            Dim responseText As String = Await RequestAccessToken(code, redirectUri)

            Dim parser As OAuthResponseParser = New OAuthResponseParser()

            Dim user = parser.EmailInIdToken
            Dim accessToken = parser.AccessToken

            Console.WriteLine("User: {0}", user)
            Console.WriteLine("AccessToken: {0}", accessToken)

            SendMailWithXOAUTH2(user, accessToken)
        End Sub

        Private Async Function RequestAccessToken(ByVal code As String, ByVal redirectUri As String) As Task(Of String)
            Console.WriteLine("Exchanging code for tokens...")

            ' builds the  request
            Dim tokenRequestBody = String.Format("code={0}&redirect_uri={1}&client_id={2}&grant_type=authorization_code",

            ' sends the request
            Dim tokenRequest As HttpWebRequest = CType(WebRequest.Create(tokenUri), HttpWebRequest)
            tokenRequest.Method = "POST"
            tokenRequest.ContentType = "application/x-www-form-urlencoded"
            tokenRequest.Accept = "Accept=text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8"

            Dim _byteVersion As Byte() = Encoding.ASCII.GetBytes(tokenRequestBody)
            tokenRequest.ContentLength = _byteVersion.Length
            Dim stream As Stream = tokenRequest.GetRequestStream()
            Await stream.WriteAsync(_byteVersion, 0, _byteVersion.Length)

                ' gets the response
                Dim tokenResponse As WebResponse = Await tokenRequest.GetResponseAsync()

                Using reader As StreamReader = New StreamReader(tokenResponse.GetResponseStream())
                    ' reads response body
                    Return Await reader.ReadToEndAsync()
                End Using

            Catch ex As WebException

                If ex.Status = WebExceptionStatus.ProtocolError Then
                    Dim response = TryCast(ex.Response, HttpWebResponse)

                    If response IsNot Nothing Then
                        Console.WriteLine("HTTP: " & response.StatusCode)

                        ' reads response body
                        Using reader As StreamReader = New StreamReader(response.GetResponseStream())
                            Dim responseText As String = reader.ReadToEnd()
                        End Using
                    End If
                End If

                Throw ex
            End Try
        End Function

        ' Hack to bring the Console window to front.
        Public Sub BringConsoleToFront()
        End Sub

        Private Declare Auto Function GetConsoleWindow Lib "kernel32.dll" () As IntPtr
        Private Declare Auto Function SetForegroundWindow Lib "user32.dll" (ByVal hWnd As IntPtr) As Int32

    End Class

End Module

VB.NET - Send Email Using Microsoft OAuth + Hotmail/Outlook Live SMTP Server in ASP.NET/ASP MVC

If you use Microsoft OAuth in ASP.NET/ASP MVC application, you should use a ASP.NET page or ASP MVC Controller to get authorization code instead of HttpListener. You need to add your ASP.NET page or ASP MVC Controller routing path to Authorized Redirect URIs in your Azure application.

' Please add http://localhost:54098/oauth/token to Authorized redirect URIs in your Google/MS Azure project.
Public Function Token(ByVal code As String) As ActionResult
    ' code parameter is the authorization code returned by MS OAuth server,
    ' then you can use it to request AccessToken
    ' just like RequestAccessToken method in previous example
End Function

You can find a full sample project in EASendMail installation path\Samples_ASPNetMvc.

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



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