Outlook account is offline in Mail

Cambs_Lad wrote:

It did take some time resetting passwords but now running Outlook mail natively.

Some have reported that, after upgrading to macOS 26, they had to remove MS accounts (Outlook; Hotmail; MSN), from Apple Mail and then reinstall them. That may be why that worked.

It appears that in the short-term this is a Microsoft issue. Microsoft announced on 2/2 that EWS was going away in October of this year, but it seems they may have done something to disable it early for some. Apple's Mail app still uses EWS to connect to M365 while the iOS/iPadOS and Outlook do not. We submitted a ticket yesterday to Microsoft after noticing no EWS connections to our Microsoft 365 tenant took place after Sunday, 2/1. As of this morning (2/5) it is now working again for our customers. In the long-term, since EWS is being retired in October, Apple's Mail app for macOS will need to be updated to use the Graph APIs vs. EWS in order to continue functioning.

You're not alone! We're experiencing the same issue across our organization. Every client that uses Apple's Mail app on macOS only are showing the same error message and can not access their mail. They have to use Outlook Online or the Outlook app. We haven't found a solution yet, and there are no real smoking guns from the client-end, even xProtect are at 2 different versions, with the same issues.

I highly doubt it's an issue with 26.2. We've been on that version for a while without an issue and have it installed on 2500 devices. It seems something happened as of this morning. We also have an open ticket with Microsoft in case they made a change that is impacting Apple Mail uses.