Why did my work email stop syncing in Mail on my Mac — and how do I fix it?

Microsoft began disabling Exchange Web Services by default in Exchange Online on October 1, 2026, and Mac Mail still relies on it to sync Microsoft 365 accounts — while iPhone and iPad are unaffected. The practical fix for now is Outlook for Mac, and only an IT admin can temporarily restore the old connection.

It is Monday morning, your Mac's Mail app is stuck showing Friday's inbox — yet the very same work account works perfectly fine on your iPhone. Short answer: This one probably is not your password, and it is not your Mac breaking. Microsoft has begun switching off an older sync technology that Apple's Mac Mail still depends on, and the practical fix for now is to use Microsoft Outlook for Mac.

Here is what is happening. Starting October 1, 2026, Microsoft began disabling Exchange Web Services — EWS — by default in Exchange Online, rolling the change out in phases. Apple's Mail and Calendar apps on the Mac still sync Microsoft 365 accounts through EWS, so some Mac users lose sync sooner than others.

Your iPhone and iPad are not affected, because they use a different system called Exchange ActiveSync, and companies running their own Exchange servers are not affected either. Apple says it is working with Microsoft to move its Mac apps to the newer Microsoft Graph system in a future macOS 27 update, but that update has not arrived yet.1. Confirm it is the Mac-only issue.

Check the account on your iPhone or in webmail. If mail flows fine there, it is this sync change — not a password problem — so stop deleting and re-adding the account, which will not help.2. Use Outlook for Mac for now.

Microsoft's own app already works with the newer Graph system, so it keeps your work mail and calendar syncing while Apple's apps catch up.3. Tell your IT department. If this is a company account, only an admin can temporarily turn EWS back on — individual users cannot flip that switch themselves.4.

Keep macOS updated. When Apple ships the Graph-based update, you will want it installed the day it lands.Pro tip: Microsoft plans to shut EWS down permanently on April 1, 2027, with no extensions planned. If you are an admin, plan the move now, while the temporary switch still exists — not next March.Ad’s take: Two giant companies, one broken handshake, and regular folks just wanting their email.

Until Apple and Microsoft sort it out, Outlook for Mac is the boring fix that works — take it and get on with your Monday.