SMTP and shared mailboxes results in AADSTS50059 return code.

[shymega]

Hi,

I'm setting up Davmail for a Microsoft 365 Business account. The setup is that there are two shared mailboxes, to which my user has access. However, even with the syntax described in #91, and on the latest version of Davmail (not trunk, will try that shortly), I'm finding Davmail chokes on the following error from Microsoft:

AADSTS50059: No tenant-identifying information found in either the request or implied by any provided credentials.

I've checked AAD, and the Davmail application has been granted access to the whole M365 organisation, so I believe permissions are correct.

The tenant ID is not set in the props, and I'm using the default OAuth 2.0 settings.

I can share some more information once I sanitize and anonymize it.

Is this a known bug? IMAP works just fine - it's only SMTP that fails.

[esabol]

Hi. I'm just an interested bystander, fwiw. Looking at the change made for a shared mailbox in PR #91, it only changed code in ImapConnection.java. I would think there would need to be some similar change to SmtpConnection.java, and I don't see one in PR #91. Just guessing, but that might be why it works for IMAP but not SMTP.

[mguessan]

splitusername wouldn't help over SMTP, the CreateItem call to send message doesn't support impersonation.

I don't even know if it's possible over EWS

[shymega]

I don't think it's possible over EWS either. I am sort of experimenting with a proxy that runs as an extension to Apache James, and using both EWS (2nd-tier, given Microsoft's position) and Microsoft Graph (1st-tier).

It's a shame EWS doesn't support shared mailboxes - seems like a huge oversight. Might be worth asking Microsoft directly, I can't see it documented. But it could be an undocumented method.

[mguessan]

I checked again the code, the send message is implemented by creating an item in the sent folder with send message flag. I am wondering if doing this on the shared mailbox sent folder would work.

That's what we do for Caldav shared mailbox access:
http://localhost:1080/users/[email protected]/calendar

Steps would be:

• provide a way to pass shared mailbox inside SMTP username
• pass it to getFolderId, path would be /users/[email protected]/Sent
• create item in this folder with SendAndSaveCopy or SendOnly flag

[shymega]

That sounds like a sane approach. I did have a look at the sources, but quickly found I was jumping between classes, just to get to the actual sendMessage logic.

If the shared mailbox was to be passed via the SMTP username - my vote would be a similar syntax to IMAP shared mailboxes.