This post covers how to enable a users Outlook integration with Dynamics 365. In summary, you will need to approve and enable a users mailbox, then make sure to add the D365 App For Outlook setting enabled.
First, Approve and Enable the users mailbox in D365.
Access Dynamics 365 CRM: Log in to your Microsoft Dynamics 365 CRM instance with appropriate permissions.
Navigate to Settings: In Dynamics 365, click on the "AdvancedSettings" option in the main menu.
Navigate to Email Configuration Tile.
The last step is to make sure the D365 for Outlook App is setup for user.
If you are having a hard time still, do not hesitate to reach out for help. We are Dynamics 365 Experts!