This issue occurs when an API request is made without access tokens. When an API request is submitted without access tokens, the error message Unauthorized!! Security setup not done for account is displayed.
Reset the Microsoft email security credentials
Solution: Repeat the procedure for setting the Microsoft email security credentials. See Configuring Connection Security.
If resetting the email security credentials does not resolve the error message, make sure REST API functionality is enabled on the Microsoft Outlook account and the scopes defined for the connection are correct. See Prerequisites for Creating a Connection and Configuring Connection Security.