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

I don't see how MS can think it's a client side issue, as several of us have one or more accounts that work and one or more that fail on the same client. In my case I was looking at a subscribed folder and disappeared before my eyes and my first thought was did I do something that deleted the folder. I have an email program that runs as a service/daemon that reads email, parses it, and based upon the contents forwards it to the appropriate email address/addresses. Recently I had to add OAuth2 login and happen to have a test program for testing OAuth2 still around. The program uses Javamail. Last night I tried to list subscribed which fails with LSUB error, tried to subscribe and it failed, and tried to check if a folder was subscribed and it failed with an LSUB error. Below is the output of the program ran against an account that doesn't work. On the account that Thunderbird can subscribe all of the commands complete normally. I don't have the capability of submitting a ticket to MS.

DEBUG: JavaMail version 1.6.2

DEBUG: successfully loaded resource: /META-INF/javamail.default.address.map

DEBUG: setDebug: JavaMail version 1.6.2

DEBUG: getProvider() returning javax.mail.Provider[STORE,imap,com.sun.mail.imap.IMAPStore,Oracle]

DEBUG IMAP: mail.imap.fetchsize: 16384

DEBUG IMAP: mail.imap.ignorebodystructuresize: false

DEBUG IMAP: mail.imap.statuscachetimeout: 1000

DEBUG IMAP: mail.imap.appendbuffersize: -1

DEBUG IMAP: mail.imap.minidletime: 10

DEBUG IMAP: closeFoldersOnStoreFailure

DEBUG IMAP: trying to connect to host "outlook.office365.com", port 993, isSSL true

* OK The Microsoft Exchange IMAP4 service is ready. ***************magic stuff ********

A0 CAPABILITY

* CAPABILITY IMAP4 IMAP4rev1 AUTH=PLAIN AUTH=XOAUTH2 SASL-IR UIDPLUS MOVE ID UNSELECT CHILDREN IDLE NAMESPACE LITERAL+

A0 OK CAPABILITY completed.

DEBUG IMAP: AUTH: PLAIN

DEBUG IMAP: AUTH: XOAUTH2

DEBUG IMAP: protocolConnect login, host=outlook.office365.com, user=email address, password=<non-null>

A1 AUTHENTICATE XOAUTH2 **************************magic stuff ***************

A1 OK AUTHENTICATE completed.

A2 CAPABILITY

* CAPABILITY IMAP4 IMAP4rev1 AUTH=PLAIN AUTH=XOAUTH2 SASL- IR UIDPLUS MOVE ID UNSELECT CLIENTACCESSRULES CLIENTNETWORKPRESENCELOCATION BACKENDAUTHENTICATE CHILDREN IDLE NAMESPACE LITERAL+

A2 OK CAPABILITY completed.

DEBUG IMAP: AUTH: PLAIN

DEBUG IMAP: AUTH: XOAUTH2

Get subscribed list

A4 LSUB "" "%"

A4 BAD LSUB failed.

A5 SUBSCRIBE Outbox

A5 BAD SUBSCRIBE failed.

A6 UNSUBSCRIBE Outbox

A6 BAD UNSUBSCRIBE failed.

Check if subscribed folder: Outbox

A7 LSUB "" Outbox

A7 BAD LSUB failed.

Java Code Fragment

try

		{

			System.out.println("Get subscribed list");

			Folder[] s = store.getDefaultFolder().listSubscribed();

		}

		catch(Exception e)

		{

		}

		Folder fs = store.getFolder("Outbox");

		System.out.println(fs);

		try

		{

			fs.setSubscribed(true);

		}

		catch (Exception e)

		{

		}

		try

		{

			fs.setSubscribed(false);

		}

		catch (Exception e)

		{

		}

		try

		{

			System.out.print("Check if subscribed folder: ");

			System.out.println(fs);

			System.out.println (fs.isSubscribed());

		}

		catch (Exception e)

		{

		}

Thank you for this great summary of the current state of knowledge!

I suppose the only thing to do now is to wait for Microsoft to...

(1.) confirm that they did indeed break the protocol,

(2.) and either fix their IMAP4 rev.1 implementation to support LSUB consistently, or push the problem that they have created themselves onto the developers of all affected MUAs by officially supporting IMAP4 rev.2 only. (Really hope the latter will not be the case; that would feel like an abuse of power and a punch in the community's gut.)

Speaking of SLAs:

Assuming an educational establishment had recently signed a contract with Microsoft concerning or including mail services provided by them,

unaware of these emerging issues for non-Outlook users and due to lacking documentation thereof. Do you see any way that such contract could be terminated early if Microsoft were not willing or able to come up with an viable solution..?

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.

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?

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.)