I have found the example of Outlook Add-in, with Single Sign-on is not working in supplied ZIP file: https://docs.microsoft.com/en-us/samples/officedev/outlook-add-in-attachments-demo/outlook-ribbon-ad...
There are number of issues, but in essence, upon communicating with locally hosted web service: /api/SaveAttachments, the token is invalid and the service keeps returning 400 error.
I have discovered that the Claim schema, referenced in SaveAttachmentsController.cs is missing: http://schemas.microsoft.com/identity/claims/scope. I also have discovered that the scope list is referenced 3 with different values:
Could you please review this solution and supply working example?