First of all sorry for the inconvenience caused to you.
As I know, this is a known issue on latest version of Outlook 2016 and Outlook 2019--Version 2104 (Build 13929.20296), the current workaround is to delete/rename this value:
But according to my research, it could work for some clients, but some couldn't, please kindly check if it could be helpful to you.
If that's invalid, considering it could work normally on previous version, as another workaround, it's suggested to disable auto-update and revert your office version via command like below:
C:\Program Files\Common Files\microsoft shared\ClickToRun\OfficeC2RClient.exe" /update user updatetoversion=16.0.13901.20462
I will continue to monitor it in latest version of Outlook client, and if there are any updates, I would post back. Also welcome other users who has any updates post here :)
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