Oracle CX Sales plugin in Microsoft outlook is inactive

Dear all,

We are trying to implement the Oracle CX Sales for Microsoft outlook. After referring to the below documentation and following all necessary steps, it was observed that CX Sales Add-in is appearing for the test user. However, it is not highlighted i.e., user is unable to access to Add-in. What could be the possible reason ? Kindly suggest if we're missing anything here.

Document referred:

Overview of Enabling the Microsoft 365 Integration

Please find the screenshot of the issue below:

Regards,

Satwik