If the email has been moved but Outlook does not see it, I woudl move her mailbox to another database.
I have found that sometimes a move can help solve these weird anomalies.
Each time we open Outlook, the synchronization process start and stop in the middle, for some reason, we cannot figure.
The less good news is that there are many grounds for this issue, and there is no “magic” solution that will help us to solve the synchronization problem in “one click.”In this article, we review the cases and the troubleshooting steps for mitigating optional causes for Outlook synchronization problems in Office 365 environment and review the specific charters of Outlook and Exchange Online environment.
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Recipients will receive a sharing link that adds the calendar to their profile.
It's easy to share the default folders in your Microsoft Exchange mailbox: just give your co-worker permission to the folder.
This is only effecting 1 user out of 5 and the other 4 aren't having any issues and all 5 machines are configured the same.
If you are making use of shared calendars in Outlook 2016 you may find that not all appointments are showing in the calendar or are disappearing.