Known Issue : Apple Mail and Calendar don't connect to Exchange EWS

Issue : In Mac Mail starting 9/22/2026 you may see the message The operation couldn't be completed. (com.apple.accounts error 3.)

Microsoft is working through a planned deprecation of Exchange Web Services EWS and on 9/22/2026 they disabled EWS on our Exchange servers.

https://learn.microsoft.com/en-us/exchange/clients-and-mobile-in-exchange-online/deprecation-of-ews-exchange-online

Apple Mail and Calendar use EWS to connect to mail server and currently do not work. The mobile versions on iOS and iPadOS use ActiveSync to connect and will continue to work and receive mail.

According to Apple Deployment Documentation, Apple is working with Microsoft to update Mail, Calendar, Contacts, Notes, and Reminders to use the Graph API in a future macOS update.

Issue: In Mac Mail starting 9/22/2026 you may see the message The operation couldn't be completed. (com.apple.accounts error 3.)

Documentation

• https://learn.microsoft.com/en-us/exchange/clients-and-mobile-in-exchange-online/deprecation-of-ews-exchange-online
• https://techcommunity.microsoft.com/blog/exchange/exchange-online-ews-your-time-is-almost-up/4492361/replies/4501001
• https://discussions.apple.com/thread/256236440?sortBy=rank
• https://ableseo.com/macos-mail-exchange-error-3/

Resolution

1. Users can switch to Outlook for Mac, which already uses Microsoft Graph API

• We fully support Outlook on Mac and Outlook on the web please use these for email.
• You can install Outlook for Mac with Office from Self Service https://colum.teamdynamix.com/TDClient/2029/Portal/KB/Article/137200/Self-Service-software-store-for-Mac
• If you like to provide apple with Apple Mail feedback please use the standard feedback form Feedback - Mail - Apple