Unable to subscribe to Office 365 IMAP folders from MUA since 2022-11-01

Anonymous
2022-11-02T07:33:01+00:00

I'm using Thunderbird to access my Office 365 mail account and it has been working fine (a couple of month ago I also switched to OAuth2 due to deprecation of basic IMAP authentication). However, since 2022-11-01, Thunderbird is unable to subscribe to IMAP folders. Last time I know it was working was last Friday 2022-10-28. Thunderbird is able to list to available folders (e.g. when opening the "Subscribe" dialog from the mail account settings), but cannot subscribe to them. I enabled IMAP logging in Thunderbird, and it shows that the server answer the subscribe request with "BAD SUBSCRIBE".

It is not a password/authentication issue, as Thunderbird can still see the content of "Inbox" and "Deleted Items". And if I disable the option "Show only subscribed folders", it can access everything in my Office 265 account.

Edit: here's the relevant logs from Thunderbird (note: I've replaced the actual folder name with "xxxx"):

[Parent ...: IMAP]: I/IMAP ...:outlook.office365.com:A:SendData: 76 subscribe "INBOX/xxxx"

[Parent ...: IMAP]: I/IMAP ...:outlook.office365.com:A:CreateNewLineFromSocket: 76 BAD SUBSCRIBE failed.
Microsoft 365 and Office | Subscription, account, billing | For business | Other

Locked Question. This question was migrated from the Microsoft Support Community. You can vote on whether it's helpful, but you can't add comments or replies or follow the question.

0 comments

106 answers

Sort by: Newest
Most helpful Newest Oldest
  1. Anonymous
    2022-12-06T19:58:07+00:00

    I am not an admin, just an annoyed user. Hence I cannot open a tenant support ticket.

    Feel free to reference my 'results' though. And tell me which information would be required to convince the support team that the issue is indeed host-independent. I just want this mess to get sorted out ASAP.

    Was this answer helpful?

    0 comments
  2. Anonymous
    2022-12-06T19:51:47+00:00

    I really doubt that it is the client side:

    The issue persists for me on two different systems, on one I even tried a fresh install of Thunderbird.

    Assuming it were the client, then why am I not seeing these issues with my other 4 IMAP accounts on same MUA?

    (The functional ones are not Microsoft O365 accounts - of course.)

    Then you reproduced the problem in the way I was asked to reproduce it. Did you update your ticket with that info? Is it a bad idea to put our ticket numbers on this site?

    Was this answer helpful?

    0 comments
  3. Anonymous
    2022-12-06T19:32:17+00:00

    I really doubt that it is the client side:

    The issue persists for me on two different systems, on one I even tried a fresh install of Thunderbird.

    Assuming it were the client, then why am I not seeing these issues with my other 4 IMAP accounts on same MUA?

    (The functional ones are not Microsoft O365 accounts - of course.)

    Was this answer helpful?

    0 comments
  4. Anonymous
    2022-12-06T19:12:31+00:00

    Thanks for keeping this going. I just got off a call with my support team and they are still thinking it is something on the client. I have to get my affected users to login on different hosts and reproduce the problem. I asked if LSUB is still the supported way to get subscribed folders and they will ask. They are not convinced it is something on the server yet.

    -Jonathan

    Was this answer helpful?

    0 comments
  5. Anonymous
    2022-12-05T21:24:45+00:00

    On the length of account names, nothing I have noticed. I have a mix of affected and unaffected accounts with similar length, and one affected account that is just four characters.

    The way the test script works, is that handles the Oauth2 authentication at the start of the script - and after that, the connection is open/authenticated and it is just sending a series of IMAP commands interactively with the server.

    If you look below, this is the Microsoft script running against one of my affected accounts - but in this case, I commented out the last line which does a CLOSE on the IMAP session, and that leaves the session open for me to send my own commands to the server. The two commands with the green arrows are ones I have just shoved in and you can see the LSUB command fails as it did in the script.

    So I don't think this is going to be related to authentication.

    Was this answer helpful?

    1 person found this answer helpful.
    0 comments