Solved "LSUB failed" with Office 365 IMAP server

nafmo

Hi!

For the last few days, I can no longer access mail using Office 365's IMAP server (outlook.office365.com), the mail client stops with the error "LSUB failed". Looking at the debug log, I see that it completes the LIST command, but the follow-up LSUB command fails:

Listing mailboxes...
C: W5 LIST "" "*"
S: * LIST (\HasNoChildren) "/" Anteckningar
S: * LIST (\HasNoChildren) "/" Archive
S: * LIST (\HasNoChildren \Trash) "/" "Borttagna objekt"
S: * LIST (\HasNoChildren) "/" Drafts
S: * LIST (\Marked \HasNoChildren) "/" INBOX
[...cut...]
S: W5 OK LIST completed.
C: W6 LSUB "" "*"
S: W6 BAD LSUB failed.

This causes the email client to emit an "LSUB failed" error and stop processing:

background-common-bundle.js:1 [2022-11-04T07:34:28.032Z][imap-client] error listing folders: Error: LSUB failed.
Error: LSUB failed.
    at Object.callback (chrome-extension://mpognobbkildjkofajifpdfhcoklimli/background-common-bundle.js:1:500076)
    at wt._handleResponse (chrome-extension://mpognobbkildjkofajifpdfhcoklimli/background-common-bundle.js:1:504059)
    at wt._parseIncomingCommands (chrome-extension://mpognobbkildjkofajifpdfhcoklimli/background-common-bundle.js:1:503238)
    at wt._onData (chrome-extension://mpognobbkildjkofajifpdfhcoklimli/background-common-bundle.js:1:501216)
    at u.ondata (chrome-extension://mpognobbkildjkofajifpdfhcoklimli/background-common-bundle.js:1:498654)
    at u._emit (chrome-extension://mpognobbkildjkofajifpdfhcoklimli/background-common-bundle.js:1:626779)
    at u._onData (chrome-extension://mpognobbkildjkofajifpdfhcoklimli/background-common-bundle.js:1:625378)
    at chrome-extension://mpognobbkildjkofajifpdfhcoklimli/background-common-bundle.js:1:625130
(anonymous) @ background-common-bundle.js:1
Entering state: 5
Closing connection...

Access was working a few days ago, so it might be a server-side change. RFC 9051 from last year does list "LSUB" as deprecated, but also refers back to the previous specification for how to use it. Maybe Microsoft removed support for the command? The server claims to be an IMAP4rev1 server, though, 9051 is rev2:

C: W1 CAPABILITY
S: * CAPABILITY IMAP4 IMAP4rev1 AUTH=PLAIN AUTH=XOAUTH2 SASL-IR UIDPLUS ID UNSELECT CHILDREN IDLE NAMESPACE LITERAL+
S: W1 OK CAPABILITY completed.

This is unrelated to the recent login issues (I have switched to OAuth login, and that is working fine, I see the LSUB error no matter how I log in).

(Vivaldi 5.5.2805.42 (Stable channel) stable, 64-bit Linux, version a27d42632a79b549cfe6a32ddf2f26f6e03e6530)

nafmo

Good news is that as of 2023-01-24, Microsoft has fixed their IMAP server, so it once again is possible to use them. Took them almost three months, though.

FCalderoni

Same problem here.
No idea of possible causes

nafmo

@FCalderoni Thanks for the feedback. I've filed it as VB-92861 now. I have also raised it with my company's IT support contact, so we'll see which produces a result first.

It is still not working as of this morning.

gmg

@nafmo

Yes, looks like we need to switch to LIST (SUBSCRIBED) in one spot.
Very nice report. Thank you. I'm looking at this

P.s. wondering when this happened (maybe some unsubscribed thing, or maybe Office365 just deprecated LSUB now?)

nafmo

@gmg Might be a part of the recent update where they started deprecating password-based login. Still waiting for our IT support to dig up answers.

Yorks

@gmg
@nafmo
@FCalderoni

This is unlikely to be a Vivaldi problem as the same issue has been noted across a number of different MUAs connecting to O365 mailboxes and seems to have started at the beginning of November which would tie in with the original post on here.

See the following threads:

https://answers.microsoft.com/en-us/msoffice/forum/all/unable-to-subscribe-to-office-365-imap-folders/c9273f2c-b63c-4647-87ce-bab6625814e6?

https://support.mozilla.org/en-US/questions/1395442#answer-1545253

Hope this helps.

becm

@gmg Thunderbird issues raised on 2022-11-01.
The question would be, are there maybe still servers out there that do not (yet) support LIST (SUBSCRIBED) "" "*"?
And how many of those misreport their capability name (as MS servers currently seem to)?

Not sure from the Thunderbird Bugzilla discussion if they are actually aware of "MS dropped support for LSUB despite still reporting IMAP4rev1".

@Yorks so it is a client problem (in a sense), everybody affected uses a deprecated interface/command.

Yorks

@becm I see your point, but equally, it is for Microsoft to explain:

*Why this affects some but not all O365 mailboxes being accessed via IMAP
*Why other mail providers evidently haven't dropped support for LSUB yet, or everyone would have noticed
*Why they haven't notified the "change" out to the O365 community in the way they tend to for other major changes (esp. given this needs development work which is completely outside of the control of those who run O365 services)
*Why they haven't notified their intentions to product owners of the popular MUAs, since so many have been caught out - including it appears, their own Outlook development team whose product is also affected when configured for IMAP

In my world, we call this "change control" and "release control" and this is an incident they need to fix unless they can prove they did both of those properly

gmg

@nafmo @Yorks @becm @FCalderoni

Ok, new build in Snapshot that you can try to see whether this fixes your issue.

https://vivaldi.com/blog/desktop/mail-search-and-toolbars-vivaldi-browser-snapshot-2867-4/

Let me know whether this fixes this issue.

Groll

@gmg
Still same error on snapshots 2867-4 (from your link) and 2867.32 (dev chanel)

gmg

@Groll
You have an LSUB failed message on latest snapshot and stable?

Groll

@gmg
now i try clean install 5.6.2867.36 (Stable channel) bud same error LSUB Failed
(on thunderbird with same address works, on FairMail android works)

Groll

@gmg

Log from console ( i change my address to [email protected])

background-common-bundle.js:1 [2022-12-07T10:37:07.175Z][imap-client] error listing folders: Error: LSUB failed.
Error: LSUB failed.
at Object.callback (chrome-extension://mpognobbkildjkofajifpdfhcoklimli/background-common-bundle.js:1:526452)
at wt._handleResponse (chrome-extension://mpognobbkildjkofajifpdfhcoklimli/background-common-bundle.js:1:530435)
at wt._parseIncomingCommands (chrome-extension://mpognobbkildjkofajifpdfhcoklimli/background-common-bundle.js:1:529614)
at wt._onData (chrome-extension://mpognobbkildjkofajifpdfhcoklimli/background-common-bundle.js:1:527592)
at u.ondata (chrome-extension://mpognobbkildjkofajifpdfhcoklimli/background-common-bundle.js:1:525030)
at u._emit (chrome-extension://mpognobbkildjkofajifpdfhcoklimli/background-common-bundle.js:1:653330)
at u._onData (chrome-extension://mpognobbkildjkofajifpdfhcoklimli/background-common-bundle.js:1:651929)
at chrome-extension://mpognobbkildjkofajifpdfhcoklimli/background-common-bundle.js:1:651681
(anonymous) @ background-common-bundle.js:1
bundle.js:1 [MAIL - [email protected]] LSUB failed.
(anonymous) @ bundle.js:1

gmg

@Groll
And this is an Office365 account?

Groll

@gmg
Yes my school use ms office365
Vivaldi Mail auto detect and OAuth works

nafmo

I see the same "LSUB failed" message with 5.6.2867.36.

Looking at the Microsoft support thread, it looks like it is a bug on Microsoft's side, still unfixed, 35 days later.

The only client that I have that is working ATM is Alpine, and it can of course not switch to the OAuth login, as that requires a built-in browser, so it will also stop working soon.

Now if I can get $EMPLOYER to migrate away from Microsoft...

gmg

@nafmo
I think I've figured out what's wrong. Looks like Microsoft doesn't say it supports List-Extended in their capabilities (which is why my fix didn't do anything) and the LSUB doesn't match the list (the real problem)

~~https://learn.microsoft.com/en-us/openspecs/exchange_standards/ms-stanoimap/32ce4709-f18f-4fdc-82c9-d6933143f595~~ Edit: Don't think this is going to fix it

Might need to work around that. We'll see what we can do. Don't know why Office365 messed up the LSUB list though

Edit: think this might need to be fixed on the server. I wonder if unsubscribing from some folders and resubscribing

gmg

@nafmo
So Alpine is working. Is Thunderbird working for you?
It sounded like it worked in Thunderbird for @Groll, but just want to make sure that is the case.

It's currently looking like this is a problem that's server side

nafmo

@gmg said in "LSUB failed" with Office 365 IMAP server:

@nafmo
So Alpine is working. Is Thunderbird working for you?

Thunderbird was working until I tried to add a new folder to it, it then lost the entire folder list, so it seems that it does not perform the LSUB command on every connect like Vivaldi does.

Alpine works, but I have the folders in the configuration file there. "Folder-Collection" does list all folders and appear selectable.

Groll

@gmg
I am sorry Thunderbird works bud only with workaround mentionend in some forums:
SERVER SETTINGS, ADVANCED, and untick the box marked "Show only subscribed folders". This effectively ignores the subscription functionality that isn't working properly, and displays all the remote folders .

wthout this shows only Inbox and delete. But program works (incomming email is showing, emai is sendend bud not showed folder...)

https://answers.microsoft.com/en-us/msoffice/forum/all/unable-to-subscribe-to-office-365-imap-folders/c9273f2c-b63c-4647-87ce-bab6625814e6?page=7