If your work email on your Mac isn't syncing today, it might well have to do with Microsoft's cut-off of Exchange Web Services (EWS).
As of October 1, 2026, Microsoft began switching off EWS by default in Exchange Online. If you haven't heard of it before, EWS is the aging protocol that Apple's Mail and Calendar apps still use to sync Microsoft 365 work accounts.
The cutoff has been signposted for a while. Microsoft stopped adding new features to EWS back in 2018, while in 2023 the company announced that it would start disabling the protocol in Exchange Online from October 2026.
It's being described as a phased rollout, so some users may be impacted sooner than others. For those affected, system admins can still turn EWS back on, but only until April 1, 2027, when it shuts down for good.
Apple says that it is "actively working with Microsoft" to move its Mac apps over to the newer Graph API in a macOS 27 update. That update has yet to arrive, but it surely won't be long before it does.
In the meantime, Outlook for Mac works just fine, and iPhone and iPad users won't be affected because they use Exchange ActiveSync rather than EWS.
