Symptoms
Authentication automatically fails and Outlook may require a password without any interaction. You may see the following sign-in prompt.
Cause
The authentication issue occurs when Outlook is trying to connect to Teams to retrieve your free/busy status, but you don't have a Teams license. This only happens with a Microsoft365 P1 license.
Resolution
To fix this issue, follow the below steps to execute a Terminal command.
-
Quit Outlook.
-
Launch Terminal on your Mac by doing either of the following:
-
Click the Launchpad icon in the Dock, type "Terminal" in the search field, then click Terminal.
-
In the Finder, open the /Applications/Utilities folder, then double-click Terminal.
-
-
In the Terminal window, enter “defaults write com.microsoft.Outlook ClassicCalendarDisableMsTeamsMeeting -int 1” (without quotes).
-
Press Enter.