Send email OAUTH2 SMTP Outlook Java

Question

I am using the scopes: mail.send, mail.readwrite, mail.read, offline_access, openid, email, and profile (although I am fairly confident I do not need all of these -> goal is to read inbox and send emails, while also getting email and name if they exist).

I am then connecting to SMTP server with the following code:

  OAuth2Authenticator.connectToSmtp("smtp-mail.outlook.com",
          587,
          user.getOutlookUid(),
          accessToken,
          true);

The code that actually connects to the server is here:

 public static SMTPTransport connectToSmtp(String host, int port, String userEmail, String oauthToken, boolean debug)
  throws Exception {

Properties props = new Properties();
props.put("mail.smtp.starttls.enable", "true");
props.put("mail.smtp.starttls.required", "true");
props.put("mail.smtp.sasl.enable", "true");
props.put("mail.smtp.sasl.mechanisms", "XOAUTH2");
props.put("mail.smtp.sasl.mechanisms.oauth2.oauthToken", oauthToken);
Session session = Session.getInstance(props);
session.setDebug(debug);


URLName unusedUrlName = null;
SMTPTransport transport = new SMTPTransport(session, unusedUrlName);
// If the password is non-null, SMTP tries to do AUTH LOGIN.
String password = "";
transport.connect(host, port, userEmail, password);

return transport;

}

Okay, now I can get to the most frustrating part... I have used the "connectToSMTP" method to connect to Gmail and it worked perfectly.

OAuth2Authenticator.connectToSmtp("smtp.gmail.com",
          587,
          user.getGoogleUid(),
          accessToken,
          true);

So ultimately my question is "what am I doing wrong?" or "what can I update to be able to send emails through Outlook"? I have seen that Outlook has a REST API, but that is plan B. Is there something different about Outlook vs Gmail?

Some things I have considered:

1. Scope did not request enough access (so I probably am asking for too much now)
2. access_token was stored incorrectly or encoded in some way (tried decoding it from base_64 which provided nothing). I am able to use my refresh_token to update the access_token so that tells me I am probably storing them correctly.
3. I tried passing null for the password. Also passed in the actual password and that WORKED, but I have the access_token and refresh_token so I shouldn't need to ask for their explicit password. Also this would be dangerous and sketchy to ask of users.
4. I tried manually connecting to the smtp server using "openssl s_client -crlf -starttls smtp -connect smtp-mail.outlook.com:587", but it seemed to think my access_token was wrong "535 5.0.0 OAuth failed: OAuth authentication failed due to Invalid token. Code -2147184118" That number when taken two's complement and converted to hex is 0x8004920a. Helped in searches but was to no avail.
5. I have done a lot of searching for this and will continue now to post this everywhere. A lot of resources for it working with Gmail, but as previously stated I already have it working for Gmail. Something seems different for Outlook. Also I have encountered lots of posts regarding email forwarding on an email client... I am semi-creating an email client so going through outlook.com settings doesn't help me.

Another concern that a buddy of mine had was that my access token was really long, contributing to what the manual smtp server claimed. It is 1188 characters long. It's something like 'EwB4Aul3BAAUo4xeBIbHjhBxWOFekj4Xy2...x9stHxi2K/VFggE=' (obviously I hid most of the characters).

Preemptive THANK YOU for anyone who offers advice or finds my issue. Especially why I can pass in the email password and that fails, but using the oauth access_token fails.

Answer 1

Try using "pop3://user:password@host:port/INBOX". to retrieve email from the inbox , more information can be found out https://javamail.java.net/docs/api/com/sun/mail/pop3/package-summary.html

Answer 2

hope this helps : https://technet.microsoft.com/en-ca/dn44016 . Properties props = new Properties(); props.put("mail.imap.ssl.enable", "true"); // required for Gmail props.put("mail.imap.auth.mechanisms", "XOAUTH2"); Session session = Session.getInstance(props); Store store = session.getStore("imap"); store.connect("imap.gmail.com", username, oauth2_access_token);