Symptoms
After you install the March 2024 security update for Microsoft Exchange Server 2019 and 2016, you receive the following error message when you run a search in Microsoft Outlook cached mode:
We're having trouble fetching results from the server. Some items may not be included in your search results.
The search works as expected if you run it in Outlook online mode or in Outlook on the web (OWA).
Resolution
To fix this issue, install the following update:
More information
For more information about these registry entries, see: How Outlook 2016 utilizes Exchange Server 2016 FAST Search.