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: