Sample code for 30+ languages & platforms
Unicode C++

Office365 Send Email using SMTP with OAuth2 Authentication

See more Office365 Examples

Demonstrates how to send email from smtp.office365.com using OAuth2 authentication.

Chilkat Unicode C++ Downloads

Unicode C++
#include <CkJsonObjectW.h>
#include <CkMailManW.h>
#include <CkEmailW.h>

void ChilkatSample(void)
    {
    bool success = false;

    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    // An Office365 OAuth2 access token must first be obtained prior
    // to running this code.

    // Getting the OAuth2 access token for the 1st time requires the O365 account owner's 
    // interactive authorization via a web browser.  Afterwards, the access token
    // can be repeatedly refreshed automatically (with no user interaction).

    // See the following examples for getting and refreshing an OAuth2 access token

    // Get Office365 SMTP/IMAP/POP3 OAuth2 Access Token
    // Refresh Office365 SMTP/IMAP/POP3 OAuth2 Access Token

    // First get our previously obtained OAuth2 access token.
    CkJsonObjectW jsonToken;
    success = jsonToken.LoadFile(L"qa_data/tokens/office365.json");

    CkMailManW mailman;

    mailman.put_SmtpHost(L"smtp.office365.com");
    mailman.put_SmtpPort(587);
    mailman.put_StartTLS(true);

    // Use your Office365 email address for the SmtpUsername.
    mailman.put_SmtpUsername(L"OFFICE365_EMAIL_ADDRESS");
    mailman.put_OAuth2AccessToken(jsonToken.stringOf(L"access_token"));

    // Create a new email object
    CkEmailW email;

    email.put_Subject(L"This is a test");
    email.put_Body(L"This is a test");
    email.put_From(L"MY_NAME <OFFICE365_EMAIL_ADDRESS>");
    success = email.AddTo(L"John Doe",L"somebody@example.com");

    // Call SendEmail to connect to the SMTP server and send.
    // The connection (i.e. session) to the SMTP server remains
    // open so that subsequent SendEmail calls may use the
    // same connection.  
    success = mailman.SendEmail(email);
    if (success != true) {
        wprintf(L"%s\n",mailman.lastErrorText());
        return;
    }

    // If SendEmail failed because of "Failed to get initial SMTP Response", then it may be 
    // a firewall or anti-virus blocking communications.
    // See https://cknotes.com/smtp-office365-com-failed-to-get-initial-smtp-response/

    success = mailman.CloseSmtpConnection();
    if (success != true) {
        wprintf(L"Connection to SMTP server not closed cleanly.\n");
    }

    wprintf(L"Mail Sent!\n");
    }