Policy
Prevent publishing to Office.com
This policy setting controls whether Outlook users can publish their calendars to the Office.com Calendar Sharing Service. If you enable this policy setting, Outlook users cannot publish their calendars to Office.com. If you disable do not configure this policy setting, Outlook users can share their calendars with selected others by publishing them to the Microsoft Outlook Calendar Sharing Service. Users can control who can view their calendar and at what level of detail.
c68727a89f36 L_PreventpublishingtoOfficeOnline Registry
Copy registry mappings
HKCU\software\policies\microsoft\office\16.0\outlook\options\pubcal\disableofficeonline (enabled) = 1
HKCU\software\policies\microsoft\office\16.0\outlook\options\pubcal\disableofficeonline (disabled) = 0 Policy notes
This policy setting controls whether Outlook users can publish their calendars to the Office.com Calendar Sharing Service. If you enable this policy setting, Outlook users cannot publish their calendars to Office.com. If you disable do not configure this policy setting, Outlook users can share their calendars with selected others by publishing them to the Microsoft Outlook Calendar Sharing Service. Users can control who can view their calendar and at what level of detail.