Office365 IMAP suddenly returns "Authenticate Failed"

Question

I have a piece of Java code (see below), which has not been changed in a while and worked two weeks ago. When I run it now, I suddenly get an "AUTHENTICATE FAILED." I get the error on two different PCs, and I have validated that the credentials used still work when I log into may office365 mailbox using the browser.

Has something changed on the office365 side I should know of?

The error I get is:

javax.mail.AuthenticationFailedException: AUTHENTICATE failed.
    at com.sun.mail.imap.IMAPStore.protocolConnect(IMAPStore.java:732)
    at javax.mail.Service.connect(Service.java:366)
    at javax.mail.Service.connect(Service.java:246)
    at my.application.input.imap.ImapMailBoxReader.processOnMessages(ImapMailBoxReader.java:69)

Digging deeper, the cause seems to be an A3 NO AUTHENTICATE failed. response (line 730 of javax.mail.IMAPStore).

The code I use is the following (using javax.mail version 1.6.2):

package my.application.input.imap;

import my.application.dao.PhysicalTransactionDao;
import com.sun.mail.util.MailSSLSocketFactory;

import javax.mail.*;
import javax.mail.search.AndTerm;
import javax.mail.search.ComparisonTerm;
import javax.mail.search.ReceivedDateTerm;
import javax.mail.search.SearchTerm;
import java.time.LocalDate;
import java.time.ZoneId;
import java.util.*;
import java.io.*;
import java.util.function.Consumer;

public class ImapMailBoxReader {

    private String host;
    private String username;
    private String password;

    public static void main(String[] args) {
        ImapMailBoxReader imapReader =  new ImapMailBoxReader(
                "outlook.office365.com",
                "myemail",
                "mypassword");
        LocalDate startDate = LocalDate.of(2022,4,1);
        LocalDate endDate = LocalDate.of(2022,7,1);
        imapReader.processOnMessages("Inbox", startDate, endDate, SomeClass::processMessage);
    }

    public ImapMailBoxReader(String host, String username, String password) {
        this.host = host;
        this.username = username;
        this.password = password;
    }

    /**
     * Returns all messages on or after the given since date, until today. If the given since date is null, all messages
     * are returned
     * @param folder the folder to search through
     * @param since the given since date
     * @param mailConsumer the consumer that will process the messages retrieved
     */
    public void processOnMessages(String folder, LocalDate since, Consumer<Message> mailConsumer) {
        processOnMessages(folder, since, null, mailConsumer);
    }

    /**
     * Runs a given mailconsumer on all messages in the given imap folder that have been received on, or after, the given
     * since date and before the given until date. If since is null, all messages are returned up to the until date.
     * If until is null, all messages are returned from the since date until now. If both are null, all messages are
     * returned.
     * @param folder the folder to search through
     * @param since if specified, only messages from this date on are returned
     * @param mailconsumer the consumer that will be executed on the messages
     */
    public void processOnMessages(String folder, LocalDate since, LocalDate until, Consumer<Message> mailconsumer) {
        try {
            Properties prop = new Properties();
            MailSSLSocketFactory sf = new MailSSLSocketFactory();
            sf.setTrustAllHosts(true);
            prop.setProperty("mail.imap.starttls.enable", "true");
            prop.put("mail.imap.starttls.enable", "true");
            prop.put("mail.imap.ssl.socketFactory", sf);

            //Connect to the server
            Session session = Session.getDefaultInstance(prop, null);
            Store store = session.getStore("imap");
            store.connect(host, username, password);

            //open the inbox folder
            Folder inbox = store.getFolder(folder);
            inbox.open(Folder.READ_ONLY);

            Message[] messages;
            if (since != null) {
                Date startDate = Date.from(since.atStartOfDay(ZoneId.systemDefault()).toInstant());
                SearchTerm newerThan = new ReceivedDateTerm(ComparisonTerm.GE, startDate);
                if (until != null) {
                    Date endDate = Date.from(until.plusDays(1).atStartOfDay(ZoneId.systemDefault()).toInstant());
                    SearchTerm olderThan = new ReceivedDateTerm(ComparisonTerm.LT, endDate);
                    SearchTerm both = new AndTerm(olderThan, newerThan);
                    messages = inbox.search(both);
                } else {
                    messages = inbox.search(newerThan);
                }
            } else if (until != null) {
                Date endDate = Date.from(until.plusDays(1).atStartOfDay(ZoneId.systemDefault()).toInstant());
                SearchTerm olderThan = new ReceivedDateTerm(ComparisonTerm.LT, endDate);
                messages = inbox.search(olderThan);
            } else {
                messages = inbox.getMessages();
            }
            for (Message m: messages) {
                mailconsumer.accept(m);
            }
            inbox.close(false);
            store.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * Will search through all attachments of the message, and will pass those with the given extension (if provided)
     * to the consumer. Note that the connection to the imap should be open for all this magic to work. this method
     * is intended to be called from a messageconsumer during the processOnMessages method from this class.
     * @param message the message for which the attachments are needed.
     * @param extension if provided, only attachments with this extension will be provided
     * @param attachmentConsumer the consumer that will process the attachments
     * @throws IOException if for some reason the attachments can't be accessed
     * @throws MessagingException for other messaging errors
     */
    public static void processOnAttachments(Message message, String extension, Consumer<InputStream> attachmentConsumer)
            throws IOException, MessagingException {
        Multipart multipart = (Multipart) message.getContent();
        for (int i = 0; i < multipart.getCount(); i++) {
            BodyPart bodyPart = multipart.getBodyPart(i);
            if (bodyPart.getFileName() != null && bodyPart.getFileName().endsWith(extension)) {
                attachmentConsumer.accept(bodyPart.getInputStream());
            }
        }
    }
}

Again, this code worked perfectly two weeks ago, nothing was changed on my side and the credentials still work...

All suggestions are appreciated.

Answer 1

You must use OAuth2, legacy security may have been deprecated. Works with Thunderbird for example. Just see how to reactivate legacy auth or use OAuth2 with your java client.

@see https://learn.microsoft.com/fr-fr/exchange/troubleshoot/administration/cannot-connect-mailbox-pop-imap-outlook to reactivate legacy

PS : To use shared mailbox, you must user mailbox name as user, and OAuth2 user + password and MFA if needed during Auth part, all that instead of old way (user@domain\sharedmailbox + password)