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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 Go Downloads

Go
    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.
    jsonToken := chilkat.NewJsonObject()
    success = jsonToken.LoadFile("qa_data/tokens/office365.json")

    mailman := chilkat.NewMailMan()

    mailman.SetSmtpHost("smtp.office365.com")
    mailman.SetSmtpPort(587)
    mailman.SetStartTLS(true)

    // Use your Office365 email address for the SmtpUsername.
    mailman.SetSmtpUsername("OFFICE365_EMAIL_ADDRESS")
    mailman.SetOAuth2AccessToken(jsonToken.StringOf("access_token"))

    // Create a new email object
    email := chilkat.NewEmail()

    email.SetSubject("This is a test")
    email.SetBody("This is a test")
    email.SetFrom("MY_NAME <OFFICE365_EMAIL_ADDRESS>")
    success = email.AddTo("John Doe","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 {
        fmt.Println(mailman.LastErrorText())
        jsonToken.DisposeJsonObject()
        mailman.DisposeMailMan()
        email.DisposeEmail()
        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 {
        fmt.Println("Connection to SMTP server not closed cleanly.")
    }

    fmt.Println("Mail Sent!")

    jsonToken.DisposeJsonObject()
    mailman.DisposeMailMan()
    email.DisposeEmail()