Prerequisite for Scenario for Outlook add-in
Outlook Version Required
Please refer to the Microsoft documentation below. Scenario for Outlook add-in supports Outlook on Windows and on a browser, e.g. outlook.com.
https://learn.microsoft.com/en-us/office/dev/add-ins/outlook/add-in-requirements
Outlook Desktop Client - Outlook Trust Center Option
'Optional connected experiences' needs to be turned ON in order to use the Outlook desktop version.
This setting is under Options > Trust Center > Trust Center Settings… button > Privacy Options > Privacy Settings… button.
Outlook Web Client - Cookies Settings
The browser’s cookies settings to allow third-party cookies.
In Google Chrome, it should be either ‘Allow all cookies’ or ‘Block third-party cookies in Incognito’ under Settings > Cookies and other site data.
In Edge, it is located under Settings > Cookies and site permissions > Cookies and data stored.