Why did Apple Mail stop syncing my Microsoft 365 account on my Mac?

Microsoft is turning off Exchange Web Services (EWS) in Exchange Online. It has been off by default, organization by organization, since October 1, 2026, and Microsoft plans to shut it down for good on April 1, 2027. Apple Mail and Calendar on the Mac still use EWS for Microsoft 365 work and school accounts, so they stop getting new mail.

Is my iPhone or iPad affected?

No. Mail on iPhone and iPad connects to Microsoft 365 a different way (Exchange ActiveSync), so it keeps working.

Will reinstalling Mail or re-adding the account fix it?

No. Microsoft's servers are refusing the connection, so nothing you change on the Mac brings it back. Your mail is safe on Microsoft's servers.

When will Apple fix Mail?

Apple says it is working with Microsoft to move Mail, Calendar, Contacts, Notes and Reminders to Microsoft Graph in a future macOS 27 update. It has not given a date.

What can I use until then?

Ask your IT department whether they can turn EWS back on for now (possible until April 1, 2027), or use a mail app that connects through Microsoft Graph, such as Microsoft's own Outlook for Mac or ChatInbox.

Apple Mail stopped syncing your Microsoft 365 account on Mac?

Updated October 29, 2026

If Mail on your Mac stopped getting new mail from your work or school account, shows a warning triangle next to it, or keeps asking for your password, it isn't your Mac. Microsoft changed something on its side, and Apple hasn't caught up yet.

What happened

Microsoft is turning off Exchange Web Services (EWS), an old way for apps to reach Microsoft 365 mailboxes. Since October 1, 2026 it has been switched off by default, one organization at a time, and Microsoft plans to shut it down for good on April 1, 2027.

Mail and Calendar on the Mac still use EWS for Microsoft 365 accounts. When your organization's turn comes, they stop syncing.

Who is affected

Mail and Calendar on a Mac with a Microsoft 365 (Exchange Online) work or school account.
Not affected: Mail on iPhone and iPad, which connects a different way.
Not affected: organizations that run their own Exchange servers, or whose IT department has kept EWS on for now.

Reinstalling won't fix it

Removing and re-adding the account, resetting your password or reinstalling macOS won't bring it back: Microsoft's servers are refusing the connection. Your mail itself is safe on Microsoft's servers, and every app that can connect again will show all of it.

Your options

Wait for Apple. Apple says it is working with Microsoft to move Mail, Calendar, Contacts, Notes and Reminders to Microsoft Graph, the newer connection Microsoft wants apps to use, "in a future macOS 27 update." It hasn't given a date.
Ask your IT department. Administrators can turn EWS back on for their organization for now, but only until April 1, 2027.
Use a mail app that connects through Microsoft Graph. Microsoft's own Outlook for Mac does, and so does ChatInbox, the app we make.

Using ChatInbox for your Microsoft 365 mail

ChatInbox is a mail app for Mac, iPhone and iPad. It connects to Microsoft 365 through Microsoft Graph, so the EWS shutdown doesn't affect it. It also works with Gmail, iCloud and other mail accounts, so you can keep everything in one place.

Your mail is organized by person, with newsletters in a separate Feeds list.
You sign in on Microsoft's own sign-in page. ChatInbox never asks for or stores your Microsoft password.
Your mail goes straight between your devices and Microsoft. It never passes through our servers.
Free to start.

To add your account

Download ChatInbox from the App Store and open it.
Type your work email address and click Continue. ChatInbox recognizes a Microsoft 365 address.
Sign in on Microsoft's page, then allow ChatInbox to read and send your mail.

Download ChatInbox on the App Store

If Microsoft says "Need admin approval"

Some organizations only let apps their IT department has approved read your mail. If you see this message, forward this to your IT department:

ChatInbox (published by Innovatism LLC) asks for these Microsoft Graph permissions, on behalf of the person signed in only: User.Read (basic profile), Mail.ReadWrite (read and organize their mail) and Mail.Send (send mail as them). It has no access to anyone else's mailbox. Application ID: 36e98cc2-c5f7-4746-84dd-789d8ed0d41a. An administrator can approve it for the organization by signing in to ChatInbox and choosing "Consent on behalf of your organization," or in the Microsoft Entra admin center under Enterprise applications.

If your organization only allows company-managed devices to reach work mail, no app outside that setup will connect. Your IT department can tell you what's allowed.

What ChatInbox doesn't replace

ChatInbox handles your mail. Its calendar shows the calendars already on your Mac, so a Microsoft 365 calendar in Apple Calendar has the same problem there until Apple's update arrives. Contacts aren't synced by ChatInbox either.

Questions

Do I have to stop using Apple Mail?

No. Keep using it for your other accounts, and use another app for your Microsoft 365 account until Apple's update arrives.

Will I lose any mail?

No. Your mail stays on Microsoft's servers. Once Mail connects again, or you sign in from another app, it's all there.

Is my iPhone affected?

No. Mail on iPhone and iPad keeps working with Microsoft 365.

Can I talk to someone?

Write to admin@innovatism.app or ask in our Discord. We answer ourselves.