Outlook.com IMAP OAuth2 fails with "User is authenticated but not connected"

I cannot receive mail from my Outlook.com account in Thunderbird. This does not appear to be a Thunderbird configuration problem. Thunderbird 159.0 on Windows. IMAP: outlook.office365.com, port 993, SSL/TLS, OAuth2, username = full address SMTP: smtp.office365.com, port 587, STARTTLS, OAuth2, username = full address The Microsoft sign-in window completes successfully and an OAuth2 token is issued and stored. Using the same token: 1. SMTP AUTH XOAUTH2 succeeds: 235 2.7.0 Authentication successful 2. IMAP AUTHENTICATE XOAUTH2 fails: NO User is authenticated but not connected. 3. POP3 AUTH XOAUTH2 fails with an authentication/protocol error I also reproduced the IMAP failure with a raw IMAP connection, outside Thunderbird. A brand-new Thunderbird profile still fails for this Outlook.com account; a Gmail account in the same profile works normally. Thunderbird is up to date. Outlook on the web works. IMAP is enabled in Outlook.com settings (toggled off and back on). The same IMAP failure happens on two different networks. I have already contacted official Outlook.com support. They said IMAP is outside their scope as long as Outlook.com works in the browser, and directed me to Feedback Hub. Is there any Thunderbird-side workaround, or any known Outlook.com IMAP OAuth2 bind issue and recommended next step?