✅ Auvik API Client - Ok in Postman, Unauthorized in client...

I have created a C# client for the Auvik API. To test the credentials I will be using, I make the validation call in Postman and I get 200 Ok response. At this point, I can be confident that the user name and api key I am using is working properly. Next, I used the Postman generated code (just to make sure it wasn't MY code that was at issue, but my code returns the same) and I get a 401 Unauthorized. See code in attached pictures. Anyone have any idea what I'm doing wrong here?