If you were using the Outlook Web Add-in prior to Riva Insight 2022.3:
you also need reach out to the Riva Success Team to enable the Graph API for your org by updating the following key in your 'CompanySettings' configuration file: <add key="OfficeJs.DataApi.Mobile" value="Graph" />
How do I get it (Insight On-Premise)?
Set up and configure a Graph Connected App in your Microsoft 365 tenant. Reach out the Riva Success Team for guidance on setting up your Graph Connected App.