ActiveSync & EWS Issue - Outlook for Microsoft 365 MSO
Problem reported by Ranjan Vaswani - 11/1/2020 at 10:28 PM
Not A Problem
I am using Outlook for Microsoft 365 MSO v16.0.13328.20262.  It is a desktop client on Windows 10.  64-bit.

My mailbox is presently configured based on ActiveSync.

My Outlook is receiving emails fine...but it is not establishing 2-way sync.  Calendar events and Contacts which I create in Outlook don't get synced.

Also, when I store emails in folders using Outlook, this doesn't get synced either.

Please advise if there's a bug and what I can do about it.

My smartermail account is enabled with EAS and EWS.

3 Replies

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Tony Scholz Replied
Employee Post

Unfortunately we are no longer supporting/troubleshooting EAS issues related to Outlook on desktop. The reason for this change in our policy is because Microsoft has ended support for EAS connections to Outlook altogether. You can learn more about Microsoft's deprecation of EAS in Outlook, and information on our supported client/protocol connections here: 
We do apologize for any inconvenience this may cause. Moving forward we will only be able to support technologies built for their intended and specific purposes. This includes:
  • EAS for mobile synchronization on iOS and Android as well as the Windows Mail, People and Calendar apps that ship with Windows 10.    
  • MAPI/EWS for desktop synchronization.
    • MAPI for Outlook for Windows.
    • EWS for Outlook for Mac, as well as other clients such as eM Client and the native MacOS applications for Mail, Contacts, Calendars, Reminders and Notes.    
  • CalDAV, CardDAV, IMAP and POP3 for virtually all mobile and desktop clients
I do know that we are looking to update EAS for mobile devices. This may have some secondary effects on how EAS is working on desktop clients as well. For SmarterMail builds newer then June 3rd the EWS license should also include MAPI support. 

Thank you,
Tony Scholz
Technical Support Specialist
SmarterTools Inc.
(877) 357-6278
Michael Replied
Does this affect Build 7611 (November 2, 2020)

So how does a server migrate to the MAPI build if we have users on Outlook 16/365 currently connected with EAS? They are just broken until we migrate them to MAPI (Several days). Is that what I'm hearing?
Michael Replied
Can anyone confirm on Build 7611 or higher that EAS in Outlook 2016 is stable enough for us to first upgrade then slowly migrate EAS users over to IMAP over several days?

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