When I start Thunderbird (31.2.0 under Ubuntu 14.04), my Outlook 365 account [email protected] accessed over IMAP is completely unreachable (I can't even see the list of folders, even though I have local archives). I see the following message in a D-Bus notification (several times):

The current operation on 'Inbox' did not succeed. The mail server for account [email protected] responded: User is authenticated but not connected.

This account has been working for a while. I changed my password during my previous Thunderbird session; after entering the new password, Thunderbird still worked.

What does this seemingly nonsensical message “User is authenticated but not connected” mean? How do I get my email?

  • I had this exact problem on Mac OS X 10.10.1 Yosemite, also accessing an Office 365 account over IMAP using Mozilla Thunderbird 31.2.0. The proposed fix worked perfectly. I also had to resync the account's folders as they had apparently been deleted locally. Also in my case, the issue appeared after I changed my password. I've done this several times before without problem. A possible contributing reason might be that I this time changed the password directly in AD, rather than through any user-side facilities.
    – anlag
    Commented Dec 1, 2014 at 13:01

3 Answers 3


The message “User is authenticated but not connected” is due to a bug in the Exchange server's IMAP implementation. If the client presents a valid user name but an invalid password, the server accepts the login, but subsequent commands fail with the aforementioned error message. Source: SaneBox blog.

So I need to change the password stored by Thunderbird. There's no actual way to change the password except at a password prompt (which Thunderbird doesn't show since the server never tells it that the password is invalid). I first need to make Thunderbird forget my saved password: use the “Preferences” → “Preferences” menu, go to the “Security” → “Passwords” tab, click the “Saved Passwords...” button and remove the entry(s) that have the old password.

I don't know why I still had the old password there. It's possible that Thunderbird had worked after the password change only because existing connections had remained open.

I then restarted Thunderbird (I couldn't find an easier way to make it re-attempt to connect to the Exchange server).

Thunderbird deleted all my local archives for this account. I think it decided that the folders had been deleted on the server when it received an unknown error from the server, instead of treating the error as an error. This is a bug in Thunderbird, I haven't tracked it down. When I subsequently changed my password again, I closed Thunderbird first, and it didn't delete any archives.


I have this problem from time to time. Most recently I tried changing the "maximum number of connections to cache" to 1 and it solved the problem (possibly just a coincidence but it was correlated enough to post here)..

You can do this under Edit->Account Settings->Server Settings->Advanced...


Two steps are required, disabling IPv6 per Kenneth Hoste as well as upgrading to Thunderbird 107.0b3 or later.

  1. Menu > Settings 2. "Gear" tab > scroll to bottom > click "Config Editor" 3. Search for: IPv6 4. Toggle network.dns.disableIPv6 to true

According to the Thunderbird blog, you need to use Thunderbird 107.0b3 or later. This fixed the error that

User is authenticated but not connected

From the blog post itself:

In a coming release of the Thunderbird 102.x series, we will be making some changes to the way we handle OAuth2 authorization with Microsoft accounts, and this may involve some extra work for users currently using Microsoft-hosted accounts through their employer or educational institution.

In order to meet Microsoft’s requirements for publisher verification, it is necessary for us to switch to a new Azure application and application ID. However, some of these accounts are configured to require administrators to approve any applications accessing email.

We have already made the necessary changes in the current Thunderbird beta series.

If you are using a hosted Microsoft account, please temporarily launch Thunderbird 107.0b3 or later (download here) and attempt to log in, making sure to select “OAuth2” as your authentication method.

If you encounter a screen saying “Need admin approval” during the login process, please contact your IT administrators to approve the client ID 9e5f94bc-e8a4-4e73-b8be-63364c29d753 for Mozilla Thunderbird (it may appear to admins as “Mzla Technologies Corporation”).

We request the following permissions:


After doing this, you may return to using the version you were using previously.

  • 4
    I ran into the "User authenticated but not connected" problem recently (started on 28 Dec 2022 for me), and after a bit of searching I found that disabling IPv6 in Thunderbird fixed the problem for me, as was suggested in this Thunderbird bug report: bugzilla.mozilla.org/show_bug.cgi?id=1797951 (see also support.mozilla.org/en-US/questions/1399126) Commented Dec 31, 2022 at 10:00
  • Ran into this now - Oct 2023. Turning off IPV6 solved the problem. GoDaddy Office365 email hosting with Thunderbird 115. Thanks!
    – CanuckT
    Commented Oct 7, 2023 at 4:11

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