We use Office 365 and I was trying to use the Calendar Passer Client and had a lot of issues.
The first problem is that the AutoDiscovery was not working correctly for me. When I started the client it would hang for at lease 3 minutes. I finally figured out it was the AutoDiscovery that was taking all the time.
The second problem that I had was that I could not authenticate. The code does an OAuth token authenticate. The problem for me was that the "CalendarPasserClient" needed to be registered with Azure AD for the OAuth to work. I needed to go to my Azure AD portal and add the application manually. Here the information that you will need for registering the "CalendarPasserClient" with Azure AD.
Name: CalendarPasserClient
Application Id: ed0badb4-aa5e-40b2-814b-18a5086743f3
Hope this helps someone else.
