MS365 IMAP+OAUTH2 Fails in Mail Clients

Question

For some time now, I've been trying to enable IMAP access to my user on a tenant in order to debug if an issue is specific to Microsoft Outlook clients or other ones.

In this tenant, my user is enabled for Authenticated SMTP and IMAP for access to mail. Unfortunately, while this works fine for one tenant of mine, it fails for another with the corresponding error messages of "S: 3 BAD User is authenticated but not connected." from the server.

This is confirmed with the Microsoft Remote Connectivity Analyzer at https://testconnectivity.microsoft.com/tests/O365Imap/input which gives the same error codes.

My user is enabled for Authenticated SMTP and IMAP in the MS365 admin panel, but still gets this error, suggesting something is fubar with the MS365 side of things.

CAPs are bypassed in this case because I've got a network range as a Trusted Network for this.

Any ideas for testing/fixing?

Answer 1

Hi @Thomas Ward,

If this issue is also occurring to Outlook clients configured with IMAP, please consider creating a service request in Microsoft 365 admin center to contact support to check in backend.

Thanks for your understanding.

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