2052221 - Exchange365 shared mailboxes sometimes access incorrect mailbox

Status: UNCONFIRMED

(MailNews Core :: Networking: Exchange, defect)

Description

[osavill]

Attachment: Screenshot_20260702_154431.png

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:152.0) Gecko/20100101 Firefox/152.0

Steps to reproduce:

Attempt to access a Shared Mailbox in Exchange365 using "Exchange" as the mailbox type:
Add mail account using the Shared Mailbox's email address
At the OAUTH2 sign-in box select sign in with a different user
Sign in using the credentials of a member of the Shared Mailbox

Actual results:

The email displayed is that of the user used to sign in with

This doesn't always happen, but when it does, it is not immediately recoverable. T'bird seems to remember the sign in association, deleting the account and re-signing in does not correct this.

Expected results:

The contents of the Shared Mailbox should have been displayed.
This worked in 140, but all the current stable, beta and daily build exhibit this behaviour.

I've attached a screenshot of 140 vs 154 for a mailbox that has gone wrong. The window in black is 154, and the one in the foreground 140 ESR

Recreating the mailbox but using IMAP as the mailbox type fixes the issue.

Comment 1

[Eleanor Dicharry]

EWS was not an option in 140.

To clarify - Are you using an IMAP account in 140 and and EWS account in 152?

Comment 2

[osavill]

Yes, sorry for the confusion. 140 is using only IMAP. I tried EWS for all account in 152, but had to fall back to IMAP for the labtest@igennus shared mailbox.

I am often seeing phantom messages in my in box. As best I can see, these are mails that 140 has, via filters, moved in to the it@igennus shared mailbox. I'll attach a new screenshot

Comment 3

[osavill]

Attachment: image.png

Image showing phantom messages in the main EWS mailbox. T'brid 140 applied filters and moved these emails across to the it@igennus shared mailbox

Comment 4

[Eleanor Dicharry]

Sorry, I just want to clarify again. Shared mailboxes are not supported in Thunderbird via EWS. So you're only seeing this behavior with IMAP, correct?

Comment 5

[osavill]

Yes, that is correct.

Sometimes, after clicking away and clicking back on the folder, the column sort is reset.