Attendees receive a meeting cancellation followed by a meeting update shortly before the start time

Applies to: Exchange OnlineExchange Server 2016 Enterprise EditionExchange Server 2016 Standard Edition


Consider the following scenario:
  • A meeting organizer creates a meeting that includes one or more external recipients.
  • One or more of the external recipients has a hidden mail contact in the global address list.
  • The organizer closes the reminder on his or her Apple iOS device.
In this scenario, the external attendee receives a meeting cancellation followed by a meeting update that corrects the original cancellation. Internal users may receive an additional meeting update.


An update to Exchange ActiveSync (EAS) that was intended to improve general protocol functionality exposed a pre-existing issue with the underlying system code, which causes this calendar synchronization issue.


Make the hidden contact visible in the global address list by using the Set-MailContact cmdlet. To do this, do one of the following:
  • In Exchange Online, follow these steps:
    1. Connect to Exchange Online by using remote PowerShell. For more information, see Connect to Exchange Online using remote PowerShell.
    2. Run the following command:
      Set-MailContact <alias> -HiddenFromAddressListsEnabled:$False 
  • In on-premises Exchange Server 2016 and in an Exchange hybrid environment, open the Exchange Management Shell, and then run the following command:
    Set-MailContact <alias> -HiddenFromAddressListsEnabled:$False 
You can also work around this issue by using Microsoft Outlook for iOS.
Microsoft is researching this issue and will post more information in this article when the information becomes available.

More Information

For more information about the Set-MailContact cmdlet, see go to Set-MailContact.