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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 features that help users manage their subscriptions, account settings, and billing information.
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.
That is some first class technical support. The irony is that our orgs/companies are all happily paying for that support, so why would MS bother?
Thank you for mentioning the Thunderbird workaround!
I was contacted by Microsoft support who claimed that IMAP is no longer supported since Jan 1 2023. I cannot find any mention of it online, perhaps the representative was refering to IMAP Basic Auth being deprecated. https://techcommunity.microsoft.com/t5/exchange-team-blog/basic-authentication-deprecation-in-exchange-online-september/ba-p/3609437
First I want to thank everyone who has collaborated on pinning down this issue. This bug is stalling our organization's migration from G Suite to Office 365, since forcing every user onto the Outlook desktop app is not an option for us.
I have opened a support ticket with Microsoft pointing to this thread, requesting to be notified when the bug has been fixed.
- Am I correct that there is currently no known work-around to this bug?
- Is this bug acknowledged by MS and listed on some public bug tracker or similar where progress may be monitored?
From what we collectively know about the issue, it's highly unlikely it will affect "every user" you migrate. It will likely just be a small percentage of them - but there is no way of knowing in advance what percentage and which ones as we don't know what is actually causing it yet (and neither it seems, do Microsoft).
As David L says, there is a relatively simple (one tick-box) workaround for affected Thunderbird users, but if you plan to use some other IMAP mail client, you'd need to look at whether there is equivalent functionality in the settings of that product to override IMAP Subscription, which is the bit that is broken for affected users.
Hello! To your questions:
First I want to thank everyone who has collaborated on pinning down this issue. This bug is stalling our organization's migration from G Suite to Office 365, since forcing every user onto the Outlook desktop app is not an option for us.
I have opened a support ticket with Microsoft pointing to this thread, requesting to be notified when the bug has been fixed.