If you use a Mac and rely on Apple Mail for your work or personal Microsoft Exchange / Microsoft 365 accounts, you may have recently been hit by a frustrating pop-up:

The operation couldn’t be completed. (com.apple.accounts error 3.)

Suddenly, none of your Exchange accounts will authenticate. You enter the correct password, pass multi-factor authentication (MFA) on Microsoft’s sign-in page, and then… boom. macOS throws Error 3 and refuses to connect. Even worse, removing and re-adding the account often wipes local cached data without resolving the problem.

Is this an isolated glitch on your Mac? No. It is a widespread issue affecting thousands of macOS users worldwide. Here is what is actually going on behind the scenes—and how you can get your email working again right now.

What Is Actually Causing com.apple.accounts error 3?

At a glance, it looks like Microsoft and Apple are playing a game of finger-pointing. However, the root cause comes down to a security protocol transition gap between the two tech giants:

1. Microsoft is shutting down legacy protocols: Microsoft has been actively phasing out an outdated background protocol called Exchange Web Services (EWS) in favour of their modern, secure Microsoft Graph API. As part of this push, Microsoft released security baselines allowing organisations to block EWS globally.
2. Apple Mail for Mac still relies on EWS: While Apple updated iOS (iPhone/iPad) Mail to connect via modern Graph APIs, macOS Mail still relies on legacy EWS endpoints behind the scenes to handle mailbox provisioning and account discovery.
3. The Handshake Fails: When you sign in on a Mac, you successfully log in on Microsoft’s side, but when macOS Mail attempts to finish setting up the inbox using EWS, Microsoft’s server blocks it. macOS can’t parse the block, resulting in the cryptic com.apple.accounts error 3.

How to Fix It (4 Actionable Solutions)

We prefer SOLUTION 4 by the way!

Because this error stems from a system-level compatibility gap, standard troubleshooting like re-typing passwords or restarting your Mac won’t fix it. Use these options instead:

Solution 1: Use the Official Microsoft Outlook App (Recommended by Microsoft)

The fastest and most reliable fix is to bypass Apple’s native account framework entirely.

• Download Microsoft Outlook for Mac from the Mac App Store (or via your M365 subscription).
• Add your Exchange account inside Outlook.
• Why it works: Microsoft Outlook uses modern REST/Graph APIs natively, bypassing the legacy EWS protocol that triggers Error 3.

Solution 2: Use Outlook on the Web

If you don’t want to install new software, navigate to outlook.office.com in Safari or Chrome. You can sign in immediately and access all your emails, calendars, and contacts without any macOS system errors.

Solution 3: Have Your IT Admin Check “EWS” Settings (Work/School Accounts)

If your email is managed by an IT department or M365 administrator, ask them to check the organisation’s security baseline in the Microsoft 365 Admin Centre:

• The Fix: Request that the administrator temporarily unblock or whitelist Exchange Web Services (EWS) for your user account or tenant. Once EWS access is granted, Apple Mail will be able to complete its setup handshake.

Solution 4: Wait for Apple’s Upcoming macOS Update

Apple is actively working on updating macOS Mail to fully support Microsoft Graph APIs ahead of Microsoft’s permanent global EWS shutdown. Once Apple rolls out this system update, native Mac Mail integration with Exchange Online will be restored.

Summary for Mac Users

If you are stuck in a loop trying to re-add your Microsoft accounts to Mac Mail, stop deleting and re-adding them. The issue isn’t your password or your device.

Until Apple releases a native update switching Mac Mail over to Microsoft Graph, switching to Outlook for Mac or Webmail is the best way to keep your workflow moving without interruption.

Have you encountered Error 3 on your Mac? Let us know in the comments below…